diff --git a/MaterialLib/SolidModels/CreateEhlers.h b/MaterialLib/SolidModels/CreateEhlers.h
index 1f80ef3eac99988a73bc79458e3551e0afb6e870..406bfb3247ec76b750384c8c9ba415c811bea47f 100644
--- a/MaterialLib/SolidModels/CreateEhlers.h
+++ b/MaterialLib/SolidModels/CreateEhlers.h
@@ -11,14 +11,17 @@
 
 #include <logog/include/logog.hpp>
 
-#include "MechanicsBase.h"
 #include "ProcessLib/Utils/ProcessUtils.h"  // required for findParameter
+
 #include "Ehlers.h"
+#include "MechanicsBase.h"
 
 namespace MaterialLib
 {
 namespace Solids
 {
+namespace Ehlers
+{
 template <int DisplacementDim>
 std::unique_ptr<MechanicsBase<DisplacementDim>> createEhlers(
     std::vector<std::unique_ptr<ProcessLib::ParameterBase>> const& parameters,
@@ -41,25 +44,22 @@ std::unique_ptr<MechanicsBase<DisplacementDim>> createEhlers(
     DBUG("Use \'%s\' as bulk modulus parameter.", bulk_modulus.name.c_str());
 
     //! \ogs_file_param_special{material__solid__constitutive_relation__Ehlers__kappa}
-    auto& kappa = ProcessLib::findParameter<double>(
-        config, "kappa", parameters, 1);
+    auto& kappa =
+        ProcessLib::findParameter<double>(config, "kappa", parameters, 1);
 
-    DBUG("Use \'%s\' as kappa.",
-         kappa.name.c_str());
+    DBUG("Use \'%s\' as kappa.", kappa.name.c_str());
 
     //! \ogs_file_param_special{material__solid__constitutive_relation__Ehlers__beta}
-    auto& beta = ProcessLib::findParameter<double>(
-        config, "beta", parameters, 1);
+    auto& beta =
+        ProcessLib::findParameter<double>(config, "beta", parameters, 1);
 
-    DBUG("Use \'%s\' as beta.",
-         beta.name.c_str());
+    DBUG("Use \'%s\' as beta.", beta.name.c_str());
 
     //! \ogs_file_param_special{material__solid__constitutive_relation__Ehlers__gamma}
-    auto& gamma = ProcessLib::findParameter<double>(
-        config, "gamma", parameters, 1);
+    auto& gamma =
+        ProcessLib::findParameter<double>(config, "gamma", parameters, 1);
 
-    DBUG("Use \'%s\' as gamma.",
-         gamma.name.c_str());
+    DBUG("Use \'%s\' as gamma.", gamma.name.c_str());
 
     //! \ogs_file_param_special{material__solid__constitutive_relation__Ehlers__hardening_modulus}
     auto& hardening_modulus = ProcessLib::findParameter<double>(
@@ -69,74 +69,62 @@ std::unique_ptr<MechanicsBase<DisplacementDim>> createEhlers(
          hardening_modulus.name.c_str());
 
     //! \ogs_file_param_special{material__solid__constitutive_relation__Ehlers__alpha}
-    auto& alpha = ProcessLib::findParameter<double>(
-        config, "alpha", parameters, 1);
+    auto& alpha =
+        ProcessLib::findParameter<double>(config, "alpha", parameters, 1);
 
-    DBUG("Use \'%s\' as alpha.",
-         alpha.name.c_str());
+    DBUG("Use \'%s\' as alpha.", alpha.name.c_str());
 
     //! \ogs_file_param_special{material__solid__constitutive_relation__Ehlers__delta}
-    auto& delta = ProcessLib::findParameter<double>(
-        config, "delta", parameters, 1);
+    auto& delta =
+        ProcessLib::findParameter<double>(config, "delta", parameters, 1);
 
-    DBUG("Use \'%s\' as delta.",
-         delta.name.c_str());
+    DBUG("Use \'%s\' as delta.", delta.name.c_str());
 
     //! \ogs_file_param_special{material__solid__constitutive_relation__Ehlers__eps}
-    auto& eps = ProcessLib::findParameter<double>(
-        config, "eps", parameters, 1);
+    auto& eps = ProcessLib::findParameter<double>(config, "eps", parameters, 1);
 
-    DBUG("Use \'%s\' as eps.",
-         eps.name.c_str());
+    DBUG("Use \'%s\' as eps.", eps.name.c_str());
 
     //! \ogs_file_param_special{material__solid__constitutive_relation__Ehlers__m}
-    auto& m = ProcessLib::findParameter<double>(
-        config, "m", parameters, 1);
+    auto& m = ProcessLib::findParameter<double>(config, "m", parameters, 1);
 
-    DBUG("Use \'%s\' as m.",
-         m.name.c_str());
+    DBUG("Use \'%s\' as m.", m.name.c_str());
 
     //! \ogs_file_param_special{material__solid__constitutive_relation__Ehlers__alphap}
-    auto& alphap = ProcessLib::findParameter<double>(
-        config, "alphap", parameters, 1);
+    auto& alphap =
+        ProcessLib::findParameter<double>(config, "alphap", parameters, 1);
 
-    DBUG("Use \'%s\' as alphap.",
-         alphap.name.c_str());
+    DBUG("Use \'%s\' as alphap.", alphap.name.c_str());
 
     //! \ogs_file_param_special{material__solid__constitutive_relation__Ehlers__deltap}
-    auto& deltap = ProcessLib::findParameter<double>(
-        config, "deltap", parameters, 1);
+    auto& deltap =
+        ProcessLib::findParameter<double>(config, "deltap", parameters, 1);
 
-    DBUG("Use \'%s\' as deltap.",
-         deltap.name.c_str());
+    DBUG("Use \'%s\' as deltap.", deltap.name.c_str());
 
     //! \ogs_file_param_special{material__solid__constitutive_relation__Ehlers__epsp}
-    auto& epsp = ProcessLib::findParameter<double>(
-        config, "epsp", parameters, 1);
+    auto& epsp =
+        ProcessLib::findParameter<double>(config, "epsp", parameters, 1);
 
-    DBUG("Use \'%s\' as epsp.",
-         epsp.name.c_str());
+    DBUG("Use \'%s\' as epsp.", epsp.name.c_str());
 
     //! \ogs_file_param_special{material__solid__constitutive_relation__Ehlers__mp}
-    auto& paremeter_mp = ProcessLib::findParameter<double>(
-        config, "mp", parameters, 1);
+    auto& paremeter_mp =
+        ProcessLib::findParameter<double>(config, "mp", parameters, 1);
 
-    DBUG("Use \'%s\' as mp.",
-         paremeter_mp.name.c_str());
+    DBUG("Use \'%s\' as mp.", paremeter_mp.name.c_str());
 
     //! \ogs_file_param_special{material__solid__constitutive_relation__Ehlers__betap}
-    auto& betap = ProcessLib::findParameter<double>(
-        config, "betap", parameters, 1);
+    auto& betap =
+        ProcessLib::findParameter<double>(config, "betap", parameters, 1);
 
-    DBUG("Use \'%s\' as betap.",
-         betap.name.c_str());
+    DBUG("Use \'%s\' as betap.", betap.name.c_str());
 
     //! \ogs_file_param_special{material__solid__constitutive_relation__Ehlers__gammap}
-    auto& gammap = ProcessLib::findParameter<double>(
-        config, "gammap", parameters, 1);
+    auto& gammap =
+        ProcessLib::findParameter<double>(config, "gammap", parameters, 1);
 
-    DBUG("Use \'%s\' as gammap.",
-         gammap.name.c_str());
+    DBUG("Use \'%s\' as gammap.", gammap.name.c_str());
 
     typename SolidEhlers<DisplacementDim>::MaterialProperties mp{
         shear_modulus, bulk_modulus, alpha,  beta,
@@ -148,5 +136,6 @@ std::unique_ptr<MechanicsBase<DisplacementDim>> createEhlers(
         new SolidEhlers<DisplacementDim>{mp}};
 }
 
+}  // namespace Ehlers
 }  // namespace Solids
 }  // namespace MaterialLib
diff --git a/MaterialLib/SolidModels/Ehlers-impl.h b/MaterialLib/SolidModels/Ehlers-impl.h
index 92b1a81733aab334786208dde66968f35bbbc631..d5415da9d24fec0872f5acb635f6bce568e9119c 100644
--- a/MaterialLib/SolidModels/Ehlers-impl.h
+++ b/MaterialLib/SolidModels/Ehlers-impl.h
@@ -41,6 +41,8 @@ namespace MaterialLib
 {
 namespace Solids
 {
+namespace Ehlers
+{
 template <int DisplacementDim>
 struct PhysicalStressWithInvariants final
 {
@@ -654,5 +656,6 @@ bool SolidEhlers<DisplacementDim>::computeConstitutiveRelation(
     return true;
 }
 
+}  // namespace Ehlers
 }  // namespace Solids
 }  // namespace MaterialLib
diff --git a/MaterialLib/SolidModels/Ehlers.cpp b/MaterialLib/SolidModels/Ehlers.cpp
index fcf2b1e6f9e850c246007f7f406639c9f44aeb1e..af91297bbd6d64e3b9dacfdc46027dd105d0e87b 100644
--- a/MaterialLib/SolidModels/Ehlers.cpp
+++ b/MaterialLib/SolidModels/Ehlers.cpp
@@ -13,8 +13,11 @@ namespace MaterialLib
 {
 namespace Solids
 {
+namespace Ehlers
+{
 template class SolidEhlers<2>;
 template class SolidEhlers<3>;
 
+}  // namespace Ehlers
 }  // namespace Solids
 }  // namespace MaterialLib
diff --git a/MaterialLib/SolidModels/Ehlers.h b/MaterialLib/SolidModels/Ehlers.h
index 0a858a00c267c53921692e997d6b55eaef077d2f..a9c14cf756f426003eade9f85e1500c2182664b8 100644
--- a/MaterialLib/SolidModels/Ehlers.h
+++ b/MaterialLib/SolidModels/Ehlers.h
@@ -36,6 +36,8 @@ namespace MaterialLib
 {
 namespace Solids
 {
+namespace Ehlers
+{
 
 template <int DisplacementDim>
 class SolidEhlers final : public MechanicsBase<DisplacementDim>
@@ -207,6 +209,7 @@ private:
     MaterialProperties _mp;
 };
 
+}  // namespace Ehlers
 }  // namespace Solids
 }  // namespace MaterialLib
 #include "Ehlers-impl.h"
diff --git a/NumLib/ODESolver/NonlinearSolver.cpp b/NumLib/ODESolver/NonlinearSolver.cpp
index fe2139c557c53100914c3439152c200fa9cb45a0..9da3ac3cc747e9a29e55936e12dae48ca9873e5f 100644
--- a/NumLib/ODESolver/NonlinearSolver.cpp
+++ b/NumLib/ODESolver/NonlinearSolver.cpp
@@ -9,9 +9,6 @@
 
 #include "NonlinearSolver.h"
 
-// for debugging
-// #include <iostream>
-
 #include <logog/include/logog.hpp>
 
 #include "BaseLib/ConfigTree.h"
diff --git a/ProcessLib/HT/HTFEM.h b/ProcessLib/HT/HTFEM.h
index 750a9de9f028b28cf486d90be4c20afb3a5d14af..880ffeed54d7d9f47fae3587380d8d0431087557 100644
--- a/ProcessLib/HT/HTFEM.h
+++ b/ProcessLib/HT/HTFEM.h
@@ -9,7 +9,6 @@
 
 #pragma once
 
-#include <iostream>
 #include <Eigen/Dense>
 #include <vector>
 
diff --git a/ProcessLib/HydroMechanics/HydroMechanicsFEM.h b/ProcessLib/HydroMechanics/HydroMechanicsFEM.h
index 97e3f0d0eabb8632963620caf89e07a81c1c4f30..fe9f0c8624fb900fbceb0b6e191f5b1ce6a2e8d3 100644
--- a/ProcessLib/HydroMechanics/HydroMechanicsFEM.h
+++ b/ProcessLib/HydroMechanics/HydroMechanicsFEM.h
@@ -9,7 +9,6 @@
 
 #pragma once
 
-#include <iostream>
 #include <memory>
 #include <vector>
 
diff --git a/ProcessLib/LIE/HydroMechanics/CreateHydroMechanicsProcess.cpp b/ProcessLib/LIE/HydroMechanics/CreateHydroMechanicsProcess.cpp
index 3c2373401e498a686317082e0174a629d6611a90..f53e2a4201b41810ca5a624dbbdb99bb10a5658a 100644
--- a/ProcessLib/LIE/HydroMechanics/CreateHydroMechanicsProcess.cpp
+++ b/ProcessLib/LIE/HydroMechanics/CreateHydroMechanicsProcess.cpp
@@ -56,7 +56,7 @@ std::unique_ptr<Process> createHydroMechanicsProcess(
     for (std::string const& pv_name : range)
     {
         if (pv_name != "pressure" && pv_name != "displacement" &&
-            pv_name.find("displacement_jump") == std::string::npos)
+            pv_name.find("displacement_jump") != 0)
             OGS_FATAL("Found a process variable name '%s'. It should be 'displacement' or 'displacement_jumpN' or 'pressure'");
         auto variable = std::find_if(
             variables.cbegin(), variables.cend(),
diff --git a/ProcessLib/LIE/SmallDeformation/SmallDeformationProcess.cpp b/ProcessLib/LIE/SmallDeformation/SmallDeformationProcess.cpp
index 548a15c5071485c5b7302225d19f1e42839078ec..1dfe9c37e02d4f352f7f3116aca5c93471f3a410 100644
--- a/ProcessLib/LIE/SmallDeformation/SmallDeformationProcess.cpp
+++ b/ProcessLib/LIE/SmallDeformation/SmallDeformationProcess.cpp
@@ -12,7 +12,6 @@
 
 #include <algorithm>
 #include <cassert>
-#include <iostream>
 #include <vector>
 
 #include "MeshLib/Elements/Element.h"
diff --git a/ProcessLib/SmallDeformation/CreateSmallDeformationProcess.cpp b/ProcessLib/SmallDeformation/CreateSmallDeformationProcess.cpp
index 1c19e13ca9926a4c993cd0d8d63deb0644558941..a00758073b60221ea72a925d56a15db406f91eb9 100644
--- a/ProcessLib/SmallDeformation/CreateSmallDeformationProcess.cpp
+++ b/ProcessLib/SmallDeformation/CreateSmallDeformationProcess.cpp
@@ -81,7 +81,7 @@ createSmallDeformationProcess(
         material = nullptr;
     if (type == "Ehlers")
     {
-        material = MaterialLib::Solids::createEhlers<DisplacementDim>(
+        material = MaterialLib::Solids::Ehlers::createEhlers<DisplacementDim>(
             parameters, constitutive_relation_config);
     }
     else if (type == "LinearElasticIsotropic")
diff --git a/ProcessLib/SmallDeformation/SmallDeformationFEM.h b/ProcessLib/SmallDeformation/SmallDeformationFEM.h
index 15b3c62c71e14153a58bdc16b500ccc3804cd27f..7f22b197a37d5870d3605003fed61eefe58d4176 100644
--- a/ProcessLib/SmallDeformation/SmallDeformationFEM.h
+++ b/ProcessLib/SmallDeformation/SmallDeformationFEM.h
@@ -27,6 +27,11 @@
 
 #include "SmallDeformationProcessData.h"
 
+namespace ProcessLib
+{
+namespace SmallDeformation
+{
+
 template <typename BMatricesType, int DisplacementDim>
 struct IntegrationPointData final
 {
@@ -77,11 +82,6 @@ struct IntegrationPointData final
     }
 };
 
-namespace ProcessLib
-{
-namespace SmallDeformation
-{
-
 /// Used by for extrapolation of the integration point values. It is ordered
 /// (and stored) by integration points.
 template <typename ShapeMatrixType>
diff --git a/ProcessLib/TES/TESLocalAssemblerInner-impl.h b/ProcessLib/TES/TESLocalAssemblerInner-impl.h
index 03dd47be1da6ec7b6638018dbcd67bc27c47aa56..767b0923cb0cdb29534b87620e22772aa77996bf 100644
--- a/ProcessLib/TES/TESLocalAssemblerInner-impl.h
+++ b/ProcessLib/TES/TESLocalAssemblerInner-impl.h
@@ -12,9 +12,6 @@
 
 #pragma once
 
-#include <cstdio>
-#include <iostream>
-
 #include <logog/include/logog.hpp>
 
 #include "NumLib/Function/Interpolation.h"
diff --git a/ProcessLib/UncoupledProcessesTimeLoop.cpp b/ProcessLib/UncoupledProcessesTimeLoop.cpp
index ab2301a1e8c92eb66619d4a385d56b294ecf46de..d6b043a727fe1682692a9b16f7a90accebcd7070 100644
--- a/ProcessLib/UncoupledProcessesTimeLoop.cpp
+++ b/ProcessLib/UncoupledProcessesTimeLoop.cpp
@@ -319,12 +319,12 @@ std::vector<std::unique_ptr<SingleProcessData>> createPerProcessData(
                 coupled_process_tree->getConfigParameterList<std::string>(
                     "coupled_process"))
             {
-                auto const& cpl_pcs_ptr = BaseLib::getOrError(
+                auto const& coupled_process = *BaseLib::getOrError(
                     processes, cpl_pcs_name,
                     "A process with the given name has not been defined.");
 
                 auto const inserted = coupled_processes.emplace(
-                    std::type_index(typeid(*cpl_pcs_ptr)), *cpl_pcs_ptr);
+                    std::type_index(typeid(coupled_process)), coupled_process);
                 if (!inserted.second)
                 {  // insertion failed, i.e., key already exists
                     OGS_FATAL("Coupled process `%s' already exists.",
@@ -509,8 +509,9 @@ bool UncoupledProcessesTimeLoop::setCoupledSolutions()
                 _per_process_data.end(),
                 [&coupled_process](
                     std::unique_ptr<SingleProcessData> const& item) {
+                    auto const& item_process = item->process;
                     return std::type_index(typeid(coupled_process)) ==
-                           std::type_index(typeid(item->process));
+                           std::type_index(typeid(item_process));
                 });
 
             if (found_item != _per_process_data.end())