I got my piece a month ago from a friend. He'd smoked tobacco out of it not that long ago, and now theres a yellow (nicotine?) stain on the inside, as well as a tobacco taste. I've used it since with no problems, but my friend doesn't like to hit it because of the taste. Last night I rinsed it in rubbing alcohol and let it soak for like 12 hours in simple green. Every spec of dirt on it was gone, but the yellow stain and tobacco taste was still there. How can i get rid of it without having to buy a new piece?
If you can find 90-99% isopropyl alcohol, use that. You don't need to fill it enough to soak the whole thing, just pour a couple cups in and then a VERY generous amount of salt. And then shake your damn heart out. The salt acts as an abrasive, getting those "hard to reach" areas. If you still have leftover stains, white vinegar might be worth a try. It works for hard water stains. EDIT: Oh, and this is probably "duh" levels of obvious, but make sure to clean ALL the parts if it's a bong/bubbler with multiple pieces. Especially the bowl.