The best and most affordable to way to clean glass pipes pipes is with simple isopropyl alcohol and salt. Regardless of if you are cleaning water pipes, steamrollers, oil rigs, or just dry smoking pipes. Simply get the highest % you can find from you local pharmacy. Empty the water pipe, rinse everything out with warm-hot water. Fill the piece with some salt, use a lot. Now add the isopropyl alcohol to the water pipe. Plug up all the holes and shake vigorously, but don’t let the piece slip out of your hand! The salt with act as an abrasive inside the water pipe and scratch loose any debris, while the rubbing alcohol acts as a solvent dissolving everything. (For extra scrubbing action you can use un-ground sea salt) Rinse thoroughly and you’re done!