diff --git a/PhysicsAnalysis/MCTruthClassifier/MCTruthClassifier/MCTruthClassifier.h b/PhysicsAnalysis/MCTruthClassifier/MCTruthClassifier/MCTruthClassifier.h
index dd6a11e00471acd8fdf89fe0d75720f54efa9acb..c627dc9f703fc5f2638e884672aa8d2c4c4d831f 100644
--- a/PhysicsAnalysis/MCTruthClassifier/MCTruthClassifier/MCTruthClassifier.h
+++ b/PhysicsAnalysis/MCTruthClassifier/MCTruthClassifier/MCTruthClassifier.h
@@ -257,8 +257,6 @@ private:
   double fracParticleInJet(const xAOD::TruthParticle*, const xAOD::Jet*, bool DR, bool nparts) const;
   void findJetConstituents(const xAOD::Jet*, std::set<const xAOD::TruthParticle*>& constituents, bool DR) const;
 #endif
-  // Now that we use TLorentzVector for the momentum base class, this is straightforward
-  template <class A, class B> inline double deltaR(A& v1, B& v2) const {return v1.p4().DeltaR(v2.p4());}
 
   static MCTruthPartClassifier::ParticleOrigin defJetOrig(const std::set<const xAOD::TruthParticle*>&) ;
 
diff --git a/PhysicsAnalysis/MCTruthClassifier/Root/MCRecoToTruth.cxx b/PhysicsAnalysis/MCTruthClassifier/Root/MCRecoToTruth.cxx
index 301c8e0c4436b7ff6886beef5c330300de22acc3..088b08f6a50d23e0c6d2f4725c5d98578b884836 100644
--- a/PhysicsAnalysis/MCTruthClassifier/Root/MCRecoToTruth.cxx
+++ b/PhysicsAnalysis/MCTruthClassifier/Root/MCRecoToTruth.cxx
@@ -6,27 +6,22 @@
 #include "AsgDataHandles/ReadHandle.h"
 #include "MCTruthClassifier/MCTruthClassifier.h"
 using namespace MCTruthPartClassifier;
-using std::abs;
 
 std::pair<ParticleType, ParticleOrigin>
 MCTruthClassifier::particleTruthClassifier(const xAOD::TrackParticle* trkPtr, Info* info /*= nullptr*/) const
 {
   ATH_MSG_DEBUG("Executing trackClassifier");
-
   ParticleType parttype = Unknown;
   ParticleOrigin partorig = NonDefined;
-
   const xAOD::TruthParticle* genPart = getGenPart(trkPtr);
   if (info) {
     info->genPart = genPart;
   }
-
   if (!genPart) return std::make_pair(parttype, partorig);
   ATH_MSG_DEBUG("trackClassifier  succeeded ");
   return particleTruthClassifier(genPart, info);
 }
 
-//-----------------------------------------------------------------------------------------
 // Not const due to ITruthParticlesInConeTool::particlesInCone
 // called via egammaClusMatch.
 std::pair<ParticleType, ParticleOrigin>
@@ -63,7 +58,6 @@ MCTruthClassifier::particleTruthClassifier(const xAOD::Electron* elec, Info* inf
   return particleTruthClassifier(genPart, info);
 }
 
-//-----------------------------------------------------------------------------------------
 // Not const due to ITruthParticlesInConeTool::particlesInCone
 // called via egammaClusMatch.
 std::pair<ParticleType, ParticleOrigin>
@@ -275,7 +269,7 @@ MCTruthClassifier::getGenPart(const xAOD::TrackParticle* trk, Info* info /*= nul
     ATH_MSG_WARNING("track matched to the truth with status " << theGenParticle->status());
   }
 
-  if (MC::isDecayed(theGenParticle) && (abs(theGenParticle->pdgId()) == 11 || abs(theGenParticle->pdgId()) == 13)) {
+  if (MC::isDecayed(theGenParticle) && (std::abs(theGenParticle->pdgId()) == 11 || std::abs(theGenParticle->pdgId()) == 13)) {
     const xAOD::TruthVertex* EndVrtx = theGenParticle->decayVtx();
     const xAOD::TruthParticle* theGenPartTmp(nullptr);
 
@@ -359,7 +353,7 @@ MCTruthClassifier::findJetConstituents(const xAOD::Jet* jet,
     // find the matching truth particles
     for (const auto *const thePart : *truthParticleContainerReadHandle) {
       // match truth particles to the jet
-      if (MC::isStable(thePart) && deltaR((*thePart), (*jet)) < m_jetPartDRMatch) {
+      if (MC::isStable(thePart) && thePart->p4().DeltaR(jet->p4()) < m_jetPartDRMatch) {
         constituents.insert(thePart);
       }
     }
diff --git a/PhysicsAnalysis/MCTruthClassifier/Root/MCTruthClassifierGen.cxx b/PhysicsAnalysis/MCTruthClassifier/Root/MCTruthClassifierGen.cxx
index 661f50d3a7ee69b709d86e5d5ddd93787ff17b67..89dbf06a9374983b78fb52103ad915b900ce74b9 100644
--- a/PhysicsAnalysis/MCTruthClassifier/Root/MCTruthClassifierGen.cxx
+++ b/PhysicsAnalysis/MCTruthClassifier/Root/MCTruthClassifierGen.cxx
@@ -323,7 +323,6 @@ ParticleType MCTruthClassifier::defTypeOfElectron(ParticleOrigin EleOrig, bool i
   return BkgElectron;
 }
 
-//-------------------------------------------------------------------------------
 ParticleOrigin
 MCTruthClassifier::defOrigOfElectron(const xAOD::TruthParticleContainer* mcTruthTES,
                                      const xAOD::TruthParticle* thePart,
@@ -366,7 +365,6 @@ MCTruthClassifier::defOrigOfElectron(const xAOD::TruthParticleContainer* mcTruth
   }
   const xAOD::TruthVertex* mothOriVert = mother->hasProdVtx() ? mother->prodVtx() : nullptr;
 
-  // to exclude interactions mu(barcode<10^6)->mu(barcode10^6)+e
   bool samePart = false;
   for (const auto & theDaug: partOriVert->particles_out()) {
     if (!theDaug)  continue;
diff --git a/PhysicsAnalysis/MCTruthClassifier/src/MCTruthClassifierAthena.cxx b/PhysicsAnalysis/MCTruthClassifier/src/MCTruthClassifierAthena.cxx
index 9c4e28fec073ee8e81bebdd294ac72cbf8a2d216..8074ffecf462421aa8e3e5b51fe30dad285783a4 100644
--- a/PhysicsAnalysis/MCTruthClassifier/src/MCTruthClassifierAthena.cxx
+++ b/PhysicsAnalysis/MCTruthClassifier/src/MCTruthClassifierAthena.cxx
@@ -3,17 +3,13 @@
 */
 
 #if !defined(XAOD_ANALYSIS) && !defined(GENERATIONBASE) // Can only be used in Athena
-
-//
 #include "MCTruthClassifier/MCTruthClassifier.h"
-//
 // xAOD EDM includes
 #include "xAODCaloEvent/CaloCluster.h"
 #include "xAODEgamma/EgammaxAODHelpers.h"
 #include "xAODTracking/TrackParticle.h"
 #include "xAODTruth/TruthParticle.h"
 #include "xAODTruth/TruthParticleContainer.h"
-//
 // Athena only includes
 #include "AthenaKernel/Units.h"
 #include "AtlasHepMC/GenParticle.h"
@@ -24,7 +20,6 @@
 
 #include <cmath>
 
-using Athena::Units::GeV;
 using namespace MCTruthPartClassifier;
 
 namespace {
@@ -51,13 +46,9 @@ std::unique_ptr<Trk::CurvilinearParameters> extractParamFromTruth(const xAOD::Tr
 }
 
 // Methods using directly the extrapolator usable only from Athena
-//-----------------------------------------------------------------------------------------
 const xAOD::TruthParticle* MCTruthClassifier::egammaClusMatch(const xAOD::CaloCluster* clus, bool isFwrdEle, Info* info) const
 {
-  //-----------------------------------------------------------------------------------------
-
   ATH_MSG_DEBUG("Executing egammaClusMatch ");
-
   const xAOD::TruthParticle* theMatchPart = nullptr;
   const EventContext& ctx = info ? info->eventContext : Gaudi::Hive::currentContext();
 
@@ -114,7 +105,7 @@ const xAOD::TruthParticle* MCTruthClassifier::egammaClusMatch(const xAOD::CaloCl
     // excluding neutrino
     if (std::abs(iParticlePDG) == 12 || std::abs(iParticlePDG) == 14 || std::abs(iParticlePDG) == 16) continue;
 
-    double pt = thePart->pt() / GeV;
+    double pt = thePart->pt() / Athena::Units::GeV;
     double q = thePart?thePart->charge():0.0;
     // exclude charged particles with pT<1 GeV
     if (q != 0 && pt < m_pTChargePartCut) continue;
@@ -184,7 +175,7 @@ const xAOD::TruthParticle* MCTruthClassifier::egammaClusMatch(const xAOD::CaloCl
         BestPartdR = dR;
       };
     }
-  } // end cycle for Gen particle
+  }
 
   if (theEgamma != nullptr) {
     theMatchPart = MC::find_matching(truthParticleContainerReadHandle.ptr(), theEgamma);
@@ -226,7 +217,7 @@ const xAOD::TruthParticle* MCTruthClassifier::egammaClusMatch(const xAOD::CaloCl
 
     if (std::hypot( detPhi(phiClus, thePart->phi())/m_partExtrConePhi, detEta(etaClus, thePart->eta())/m_partExtrConeEta ) > 1.0) continue;
 
-    double pt = thePart->pt() / GeV;
+    double pt = thePart->pt() / Athena::Units::GeV;
     double q = thePart->charge();
     // exclude charged particles with pT<1 GeV
     if (q != 0 && pt < m_pTChargePartCut) continue;
@@ -293,9 +284,7 @@ const xAOD::TruthParticle* MCTruthClassifier::egammaClusMatch(const xAOD::CaloCl
   return theMatchPart;
 }
 
-//--------------------------------------------------------------
-bool
-MCTruthClassifier::genPartToCalo(const EventContext& ctx,
+bool MCTruthClassifier::genPartToCalo(const EventContext& ctx,
                                  const xAOD::CaloCluster* clus,
                                  const xAOD::TruthParticle* thePart,
                                  bool isFwrdEle,
@@ -348,8 +337,7 @@ MCTruthClassifier::genPartToCalo(const EventContext& ctx,
 
   // create extension to sample
   std::vector<CaloSampling::CaloSample> samples = { sample };
-  std::vector<std::pair<CaloSampling::CaloSample, std::unique_ptr<const Trk::TrackParameters>>> 
-    extension = m_caloExtensionTool->layersCaloExtension(ctx, *params, samples, etaClus, caloDDMgr);
+  auto  extension = m_caloExtensionTool->layersCaloExtension(ctx, *params, samples, etaClus, caloDDMgr);
   bool extensionOK = (!extension.empty());
   if (!extensionOK) {
     ATH_MSG_WARNING("extrapolation of Truth Particle with eta  " << thePart->eta() << " , charge " << thePart->charge() << " , Pt " << thePart->pt() << " to calo failed");
@@ -363,9 +351,7 @@ MCTruthClassifier::genPartToCalo(const EventContext& ctx,
   dRmatch = std::hypot(dPhi, dEta);
 
   if ((!isFwrdEle && dRmatch > m_phtdRtoTrCut) || (isFwrdEle && dRmatch > m_fwrdEledRtoTrCut)) return false;
-
   if (!isFwrdEle && std::hypot( dPhi/m_phtClasConePhi, dEta/m_phtClasConeEta ) <= 1.0) isNarrowCone = true;
-
   return true;
 }
 #endif