With the bong, add rock salt to the bong with the rubbing alcohol. Swirl it around. The rock salt will be an abrasive to remove the dissolving tar and stuff in your bong.
A friend told me a bit of milk on top of water keeps a glass bong clean , and it seems to be working glass is spotless and it makes you change water regularly
I keep coarse sand in the bottom of my bong and give it a good swish swish every so often. It takes the gunk off and sends it right into the sink screen every time I refresh the water and sand.
That being said, it's a translucent dark blue glass piece that I made out of a vase, and I'm not sure if I would give the same treatment to a fancy roor or whatnot. But I don't own a fancy bong : ] so I'll use my ugly but effective cleaning method for now.