Best thing I've ever found to clean glass from resin and other heavy gunk is ZEP citrus degreaser -
Citrus Degreaser
You can get it at Home Cheapo for about $10.
Most bong and pipe cleaners are simply diluted versions of this concentrate, and they jack up the price 5x or more. Fill your bong and let it soak overnight, then rinse with hot water. No scrubbing, easy peasy. One gallon should last you a decade or more as it is reusable. I've had the same coffee can of solution (some mixed with water) that I've reused for the past 5 years or so, it doesn't go bad because nothing could live in it. You're welcome...