Originally Posted by Sambooka
Think of it as "seasoning" .. it is not a big deal. I have never cleaned my bowls with anything more than warm water. I smoked some very complex hookah blend last night and could pick out each of the flavors. The burnt ring won't effect taste.
If you really want to clean it, put it in some boiling water and it will loosen it up.
It's just build up of burnt carbon on your glaze
It can't affect anything at all