diff --git a/src/engine.c b/src/engine.c
index ad1673dfe71d143b1a66864a9f00ab6a6aeb9fff..fb110c0a09d7c0a91679381948786bf204837ee1 100644
--- a/src/engine.c
+++ b/src/engine.c
@@ -1716,11 +1716,6 @@ void engine_init_particles(struct engine *e) {
 
   engine_marktasks(e);
 
-  /* printParticle(e->s->parts, e->s->xparts, 1000, e->s->nr_parts); */
-  /* printParticle(e->s->parts, e->s->xparts, 515050, e->s->nr_parts); */
-
-  /* message("\n0th DENSITY CALC\n"); */
-
   /* Now do a density calculation */
   TIMER_TIC;
   engine_launch(e, e->nr_threads,
@@ -1732,15 +1727,9 @@ void engine_init_particles(struct engine *e) {
 
   TIMER_TOC(timer_runners);
 
-  /* message("\n0th ENTROPY CONVERSION\n"); */
-
+  /* Apply some conversions (e.g. internal energy -> entropy)
   space_map_cells_pre(s, 1, cell_convert_hydro, NULL);
 
-  /* printParticle(e->s->parts, e->s->xparts,1000, e->s->nr_parts); */
-  /* printParticle(e->s->parts, e->s->xparts,515050, e->s->nr_parts); */
-
-  //  exit(0);
-
   /* Ready to go */
   e->step = -1;
 }
@@ -1811,8 +1800,6 @@ if ( e->nodeID == 0 )
     message( "nr_parts=%i." , nr_parts ); */
 #endif
 
-  /* message("\nDRIFT\n"); */
-
   /* Move forward in time */
   e->timeOld = e->time;
   e->time = t_end_min;
@@ -1822,11 +1809,6 @@ if ( e->nodeID == 0 )
   /* Drift everybody */
   engine_launch(e, e->nr_threads, 1 << task_type_drift, 0);
 
-  /* printParticle(e->s->parts, e->s->xparts, 1000, e->s->nr_parts); */
-  /* printParticle(e->s->parts, e->s->xparts, 515050, e->s->nr_parts); */
-
-  /* message("\nACCELERATION AND KICK\n"); */
-
   /* Re-distribute the particles amongst the nodes? */
   if (e->forcerepart) engine_repartition(e);
 
@@ -1847,17 +1829,12 @@ if ( e->nodeID == 0 )
 
   TIMER_TOC2(timer_step);
 
+  /* Print some information to the screen */
   if (e->nodeID == 0) {
     printf("%d %f %f %d %.3f\n", e->step, e->time, e->timeStep, updates,
            ((double)timers[timer_count - 1]) / CPU_TPS * 1000);
     fflush(stdout);
   }
-
-  /* printParticle(e->s->parts, e->s->xparts,1000, e->s->nr_parts); */
-  /* printParticle(e->s->parts, e->s->xparts,515050, e->s->nr_parts); */
-
-  /* if(e->step == 2) */
-  /* exit(0); */
 }
 
 /**
diff --git a/src/runner.c b/src/runner.c
index fc17e7d3d9c860da7b262c7ebaace8950492d911..bdf32f66ea4498ff4b94168f368d171c4dc41fc4 100644
--- a/src/runner.c
+++ b/src/runner.c
@@ -515,9 +515,6 @@ void runner_doinit(struct runner *r, struct cell *c, int timer) {
 
       if (p->t_end <= t_end) {
 
-        /* if(p->id == 1000) message("init 1000!"); */
-        /* if(p->id == 515050) message("init 515050!"); */
-
         /* Get ready for a density calculation */
         hydro_init_part(p);
       }
@@ -580,9 +577,6 @@ void runner_doghost(struct runner *r, struct cell *c) {
       p = &parts[pid[i]];
       xp = &xparts[pid[i]];
 
-      /* if(p->id == 1000) message("ghost 1000"); */
-      /* if(p->id == 515050) message("ghost 515050"); */
-
       /* Is this part within the timestep? */
       if (p->t_end <= t_end) {
 
@@ -750,19 +744,6 @@ void runner_dodrift(struct runner *r, struct cell *c, int timer) {
       /* Predict the values of the extra fields */
       hydro_predict_extra(p, xp, r->e->timeOld, r->e->time);
 
-      /* if(p->id == 1000 || p->id == 515050 || p->id == 504849) */
-      /* 	message("%lld: current_t=%f t0=%f t1=%f  v=[%.3e %.3e %.3e]
-       * dh/dt=%.3e div_v=%.3e\n", */
-      /* 		p->id, */
-      /* 		r->e->time, */
-      /* 		r->e->timeOld, */
-      /* 		r->e->time, */
-      /* 		p->v[0], */
-      /* 		p->v[1], */
-      /* 		p->v[2], */
-      /* 		p->h_dt * h_inv * dt, */
-      /* 		0.333333f * p->div_v * dt); */
-
       /* Compute motion since last cell construction */
       const float dx =
           sqrtf((p->x[0] - xp->x_old[0]) * (p->x[0] - xp->x_old[0]) +
@@ -917,18 +898,6 @@ void runner_dokick(struct runner *r, struct cell *c, int timer) {
         p->v[1] = xp->v_full[1] - half_dt * p->a_hydro[1];
         p->v[2] = xp->v_full[2] - half_dt * p->a_hydro[2];
 
-        /* if(p->id == 1000 || p->id == 515050 || p->id == 504849) */
-        /*   message("%lld: current_t=%f t_beg=%f t_end=%f half_dt=%f v=[%.3e
-         * %.3e %.3e]\n", */
-        /* 	  p->id, */
-        /* 	  t_current, */
-        /* 	  p->t_begin, */
-        /* 	  p->t_end, */
-        /* 	  half_dt, */
-        /* 	  p->v[0], */
-        /* 	  p->v[1], */
-        /* 	  p->v[2]); */
-
         /* Extra kick work */
         hydro_kick_extra(p, xp, dt, half_dt);
       }
diff --git a/src/runner_doiact.h b/src/runner_doiact.h
index cddd249acd77f305a456d7b78023d4e4ca613cc7..1b987eb140569629fc4583199c58e3f33446cb78 100644
--- a/src/runner_doiact.h
+++ b/src/runner_doiact.h
@@ -1398,9 +1398,6 @@ void DOSELF1(struct runner *r, struct cell *restrict c) {
     /* Get a pointer to the ith particle. */
     pi = &parts[pid];
 
-    /* if(pi->id == 1000) message("oO 1000"); */
-    /* if(pi->id == 515050) message("oO 515050"); */
-
     /* Get the particle position and radius. */
     for (k = 0; k < 3; k++) pix[k] = pi->x[k];
     hi = pi->h;
@@ -1624,9 +1621,6 @@ void DOSELF2(struct runner *r, struct cell *restrict c) {
     /* Get a pointer to the ith particle. */
     pi = &parts[pid];
 
-    /* if(pi->id == 1000) message("oO 1000"); */
-    /* if(pi->id == 515050) message("oO 515050"); */
-
     /* Get the particle position and radius. */
     for (k = 0; k < 3; k++) pix[k] = pi->x[k];
     hi = pi->h;