You would probably have to pour a lot of alcohol through it and I doubt a cleaner would fit...my question is how would they drill the hole? Or is the stem plastic?
The stem is either plastic or a type of rubber like material. You can see the molding seam in a few of the pics and it looks like the clamp that's used to attach the bowl is cutting into the hose around the bottom [like an engine hose or something along those lines].