I want to fill the toilet bowl with water as high as I can and let the water sit without draining for up to 24 hours. Why? To let some (gentle) cleansers do their work. I've tried shutting off the water at the wall and refilling the bowl from a pitcher, but inevitably the water starts draining too soon. Ideas?
Wad up a large trash bag and stuff it into the bowl, about as far as it will go. If it's not large enough, place a few crumpled paper towels into the bag and re-wad. It should be large enough to clog most toilets, it's easy to remove, and won't seep like a towel or rag would.