diff --git a/polymer/eduke32/build/include/polymer.h b/polymer/eduke32/build/include/polymer.h
index ffeb0f433..0667543fd 100644
--- a/polymer/eduke32/build/include/polymer.h
+++ b/polymer/eduke32/build/include/polymer.h
@@ -287,6 +287,9 @@ typedef struct      s_pranimatespritesinfo {
     int32_t         x, y, a, smoothratio;
 }                   _pranimatespritesinfo;
 
+// this one has to be provided by the application
+extern void G_Polymer_UnInit(void);
+
 // EXTERNAL FUNCTIONS
 int32_t             polymer_init(void);
 void                polymer_uninit(void);
diff --git a/polymer/eduke32/build/src/engine.c b/polymer/eduke32/build/src/engine.c
index c6a4a68ba..c2446efa8 100644
--- a/polymer/eduke32/build/src/engine.c
+++ b/polymer/eduke32/build/src/engine.c
@@ -15698,7 +15698,10 @@ int32_t setrendermode(int32_t renderer)
             renderer = 3;
     }
     else if (rendmode==4)  // going from Polymer to another renderer
+    {
+        G_Polymer_UnInit();
         polymer_uninit();
+    }
 # else
     else renderer = 3;
 # endif
diff --git a/polymer/eduke32/source/actors.c b/polymer/eduke32/source/actors.c
index 606b5314e..9f895d92e 100644
--- a/polymer/eduke32/source/actors.c
+++ b/polymer/eduke32/source/actors.c
@@ -484,6 +484,23 @@ ACTOR_INLINE int32_t A_SetSprite(int32_t i,uint32_t cliptype)
 
 int32_t block_deletesprite = 0;
 
+#ifdef POLYMER
+static void A_DeletePolymerLight(int32_t s)
+{
+    polymer_deletelight(actor[s].lightId);
+    actor[s].lightId = -1;
+    actor[s].lightptr = NULL;
+}
+
+void G_Polymer_UnInit(void)
+{
+    int32_t i;
+
+    for (i=0; i<MAXSPRITES; i++)
+        A_DeletePolymerLight(i);
+}
+#endif
+
 // all calls to deletesprite() from the game are wrapped by this function
 void A_DeleteSprite(int32_t s)
 {
@@ -506,9 +523,7 @@ void A_DeleteSprite(int32_t s)
 #ifdef POLYMER
     if (getrendermode() == 4 && actor[s].lightptr != NULL)
     {
-        polymer_deletelight(actor[s].lightId);
-        actor[s].lightId = -1;
-        actor[s].lightptr = NULL;
+        A_DeletePolymerLight(s);
     }
 #endif
 
@@ -8111,9 +8126,7 @@ void G_MoveWorld(void)
                     {
                         if (actor[i].lightptr != NULL)
                         {
-                            polymer_deletelight(actor[i].lightId);
-                            actor[i].lightId = -1;
-                            actor[i].lightptr = NULL;
+                            A_DeletePolymerLight(i);
                         }
                     }
                     else
@@ -8123,9 +8136,7 @@ void G_MoveWorld(void)
                         {
                             if (!(--actor[i].lightcount))
                             {
-                                polymer_deletelight(actor[i].lightId);
-                                actor[i].lightId = -1;
-                                actor[i].lightptr = NULL;
+                                A_DeletePolymerLight(i);
                             }
                         }
 
@@ -8173,9 +8184,7 @@ void G_MoveWorld(void)
                                 {
                                     if (actor[i].lightptr != NULL)
                                     {
-                                        polymer_deletelight(actor[i].lightId);
-                                        actor[i].lightId = -1;
-                                        actor[i].lightptr = NULL;
+                                        A_DeletePolymerLight(i);
                                     }
                                     break;
                                 }
diff --git a/polymer/eduke32/source/astub.c b/polymer/eduke32/source/astub.c
index 8a5e9734e..6302cce4b 100644
--- a/polymer/eduke32/source/astub.c
+++ b/polymer/eduke32/source/astub.c
@@ -316,6 +316,11 @@ static void DeletePolymerLights(void)
             spritelightptr[i] = NULL;
         }
 }
+
+void G_Polymer_UnInit(void)
+{
+    DeletePolymerLights();
+}
 #endif
 
 extern int32_t mskip;