So my roommate bought a bong off craigslist the other day. It's a triple 3 stem perk, single dome perk zob bong. Looks really nice, but this thing is DISGUSTING. I honestly think they never cleaned it ever, and then sold it because they didn't want to lol. I've been using rubbing alcohol with salt, soaking in the tub with hot water, trying to scrap at it but getting in those perks is impossible and the shit is caked. Theres thick sticky resin in the bottom perks and smoke stains in the glass as it goes up. The rubbing alcohol and hot water has gotten off a lot, but theres still a good amount in there. Does anyone have any good methods for heavy duty cleaning?