GC a few Datums

code/modules/power/powernet.dm

@@ -29,7 +29,8 @@
 		M.powernet = null
 
 	powernets -= src
-	return ..()
+	..()
+	return QDEL_HINT_QUEUE
 
 //Returns the amount of excess power (before refunding to SMESs) from last tick.
 //This is for machines that might adjust their power consumption using this data.

code/modules/research/protolathe.dm

@@ -62,6 +62,7 @@ Note: Must be placed west/left of and R&D console to function.
 
 /obj/machinery/r_n_d/protolathe/Destroy()
 	qdel(materials)
+	materials = null
 	return ..()
 
 /obj/machinery/r_n_d/protolathe/RefreshParts()