diff --git a/src/MC/fix_mol_swap.cpp b/src/MC/fix_mol_swap.cpp
index a8871ac269..842a76593a 100644
--- a/src/MC/fix_mol_swap.cpp
+++ b/src/MC/fix_mol_swap.cpp
@@ -205,32 +205,18 @@ int FixMolSwap::attempt_swap()
     minmol + static_cast<tagint> (random->uniform() * (maxmol-minmol+1));
   if (molID > maxmol) molID = maxmol;
 
-  //printf("  Attempt %ld molID %d\n",update->ntimestep,molID);
-
   int *mask = atom->mask;
   int *type = atom->type;
   tagint *molecule = atom->molecule;
   int nlocal = atom->nlocal;
 
-  // DEBUG
-  int origitype = 0;
-  int origjtype = 0;
-
   for (int i = 0; i < nlocal; i++) {
     if (molecule[i] != molID) continue;
     if (!(mask[i] & groupbit)) continue;
-    if (type[i] == itype) {
-      origitype++;
-      type[i] = jtype;
-    } else if (type[i] == jtype) {
-      origjtype++;
-      type[i] = itype;
-    }
+    if (type[i] == itype) type[i] = jtype;
+    else if (type[i] == jtype) type[i] = itype;
   }
 
-  //printf("    ijtype %d %d orig %d %d count %d\n",
-   //      itype,jtype,origitype,origjtype,origitype+origjtype);
-
   // if unequal_cutoffs, call comm->borders() and rebuild neighbor list
   // else communicate ghost atoms
   // call to comm->exchange() is a no-op but clears ghost atoms
@@ -250,13 +236,10 @@ int FixMolSwap::attempt_swap()
 
   double energy_after = energy_full();
 
-  //printf("    eng before: %g, eng after %g\n",energy_before,energy_after);
-
   // swap accepted
 
   if (random->uniform() < exp(beta*(energy_before - energy_after))) {
     energy_stored = energy_after;
-    //printf("    accept\n");
     return 1;
 
   // swap not accepted
@@ -265,7 +248,6 @@ int FixMolSwap::attempt_swap()
   //   since will be done on next cycle or in Verlet when this fix is done
 
   } else {
-    //printf("    reject\n");
     for (int i = 0; i < nlocal; i++) {
       if (molecule[i] != molID) continue;
       if (!(mask[i] & groupbit)) continue;