For cleaning my Glass bong I remove the down tube and clean that with a drop of cilitbang, sorry, CILTIBANG,!!, as they say on the advert., drop of that on a pipe cleaner or cotton bud, that cleans all rresidue by sticking it to the cotton bud when you rub it round the sides. then quirt Ciltibang in warm water, water in the bowl wish round,.get over all the side on the inside, allow to settle for min, then swish out and rinse warm water. The citlibang dosnt strip glass but will take all the nasty stuff away with it., If you use a tube cleaner for the down tube dont brush to hard as that will screatch the glass, and my small plastic bong, 'gertrud' I take apart take gauze out and bung in my dish washer on the 45 degree c setting, low as Im not sure if thr plastic is thermo-setting or not. Its clean as new, abit faded after years of washs but clean and stink free.
If I have left my glass bong out over night with out emtpying the water I squirt cilit in and swich round, empty, then rinse and it dont smell no more. I swear by that stuff.
Take it easy..