What is the easiest and quickist and BEST way to clean a bong?

Pour in rubbing alcohol and coarse salt. Shake it around. Then you can do soap and water.

Buy a new one... it's not worth the hastle
And don't buy fancy ones, cause else you feel that you need to do he hastle, but you are doing it to yourself.

We used to just make them out of water bottles and melted biros 😂😂

Buy a few and rotate them out to sit and soak as you use the clean on. Rinse and enjoy

Hot chromo-sulphuric acid might help. 😏

Paint thinner