diff --git a/src/dobjgc.cpp b/src/dobjgc.cpp
index c44f77b80..03a715329 100644
--- a/src/dobjgc.cpp
+++ b/src/dobjgc.cpp
@@ -79,8 +79,6 @@
 #include "g_levellocals.h"
 #include "events.h"
 
-void MarkACSThinker();
-
 // MACROS ------------------------------------------------------------------
 
 /*
@@ -331,7 +329,6 @@ static void MarkRoot()
 	Mark(DIntermissionController::CurrentIntermission);
 	DThinker::MarkRoots();
 	FCanvasTextureInfo::Mark();
-	MarkACSThinker();
 	Mark(E_FirstEventHandler);
 	Mark(E_LastEventHandler);
 	for (auto &s : level.sectorPortals)
diff --git a/src/dobjtype.cpp b/src/dobjtype.cpp
index 62a810969..3d27b3a0d 100644
--- a/src/dobjtype.cpp
+++ b/src/dobjtype.cpp
@@ -242,7 +242,6 @@ void PClass::StaticShutdown ()
 {
 	if (WP_NOCHANGE != nullptr)
 	{
-		WP_NOCHANGE->ObjectFlags |= OF_YesReallyDelete;
 		delete WP_NOCHANGE;
 	}
 
diff --git a/src/p_acs.cpp b/src/p_acs.cpp
index b510ee45f..dd75f9069 100644
--- a/src/p_acs.cpp
+++ b/src/p_acs.cpp
@@ -11022,11 +11022,6 @@ CCMD(acsprofile)
 	ShowProfileData(FuncProfiles, limit, sorter, true);
 }
 
-void MarkACSThinker()
-{
-	GC::Mark(DACSThinker::ActiveThinker);
-}
-
 ADD_STAT(ACS)
 {
 	return FStringf("ACS time: %f ms", ACSTime.TimeMS());
diff --git a/src/posix/cocoa/i_video.mm b/src/posix/cocoa/i_video.mm
index 00b39639f..34cb4bb8b 100644
--- a/src/posix/cocoa/i_video.mm
+++ b/src/posix/cocoa/i_video.mm
@@ -632,7 +632,6 @@ DFrameBuffer* CocoaVideo::CreateFrameBuffer(const int width, const int height, c
 		}
 
 		old->GetFlash(flashColor, flashAmount);
-		old->ObjectFlags |= OF_YesReallyDelete;
 
 		if (old == screen)
 		{
@@ -1306,7 +1305,6 @@ void I_ShutdownGraphics()
 {
 	if (NULL != screen)
 	{
-		screen->ObjectFlags |= OF_YesReallyDelete;
 		delete screen;
 		screen = NULL;
 	}
diff --git a/src/posix/sdl/hardware.cpp b/src/posix/sdl/hardware.cpp
index e512adb73..580c5a1b0 100644
--- a/src/posix/sdl/hardware.cpp
+++ b/src/posix/sdl/hardware.cpp
@@ -95,7 +95,6 @@ void I_ShutdownGraphics ()
 	{
 		DFrameBuffer *s = screen;
 		screen = NULL;
-		s->ObjectFlags |= OF_YesReallyDelete;
 		delete s;
 	}
 	if (Video)