Reddit mentions of M&M Special Cleaner, White, 1

Thought I should write down some instructions:

• Fill bong with cleaning agent of your choice until it flows out of the bowl
  
  
• Wrap a balloon around the bowl
  
  
• Add more cleaning agent until balloon fills up
  
  
• squeeze the balloon
  
  Edit: I'm using a waterpipe cleaner called Schmand-weg

https://www.amazon.de/dp/B001G4ZFFY/ref=cm_sw_r_cp_api_AmQSzbGVDW6ZK
THIS is the best i have ever used, you dont have to rub or anything

This is what we use in europe: 1 tablespoon + boiling water, rinse after 2-3mins and it's perfectly clean. https://www.amazon.de/Wasserpfeifen-Spezialreiniger-Schmand-Weg-f%C3%BCr-Bong-Glaspfeifen/dp/B001G4ZFFY

Edit:forgot url

I used to use Isopropanol/Isopropyl Alcohol, however some time ago I got a German bong cleaner from Amazon and it honestly does a fantastic job separating the tar that gets stuck to my glass.

Fill up a bowl with hot water adding the powder as per instructions, put your pipe/bowl in there, shake it a bit and leave for about 5 minutes, then shake it again and rinse a fair bit. This seemed to get rid of some tar residue that ISO just wasn't getting at.

https://www.amazon.co.uk/Water-Special-Cleaner-Schmand-Weg-Bongs/dp/B001G4ZFFY