I went to my growshop and picked up some stuff, which included ROOR Bong cleaner. I was alittle skeptical to see if it actually worked good because I've used bong cleaners before which totally sucked, I could have done a better job licking it clean. :wtf:
So I squirt this stuff in my bong and leave it for about 10 mins, also left the down pipe, ash catcher and bowl soaking in a tub.
When I come back, swirl this stuff around a bit, tip it out and run off with hot water... to my surprise it was so fucking clean I could literally see my reflection in it, it was probably cleaner than the day I bought it!
It cost just £7 (about $15) and works like a fucking charm. I'd recommend it even for the dirtiest of bongs.