i got a hold of a cheap bubbler with a hole in the side of the bowl that leads directly into the chamber and is not connected to the downstem, so when anyone tries to clear it, they are just draw unfiltered smoke coming straight from the bowl and not passing thru the water.. what material can i use to fill up the hole(i.e. types of clay or some similar material)? The material will be going in the bowl piece so it needs to be able to withstand direct contact with a flame and contact with the cherried bud.