I can use add_struct() to mark an area of dynamically allocated memory that will then be saved when calling game_save()with SV_STRUCT.

My question is, once i have marked an area with add_struct, is there any way to unmark it? (say i allocate an area of memory to store an object, then that object is destroyed in game, so i release the memory). If there is no way to un-mark the memory, what happens when i have game_save() save an area of memeory that is no longer valid?