Soak in white vinegar for a few hours. Clean it and repeat until it looks new. Vinegar dissolves hard water and ‘other’ difficult deposits better than anything else and it’s dirt cheap.anyone know a good way to clean a glass weed pipe? i don't care so much about saving the resin i just have a few that are rank tasting and clog up rather easily. they're all about the size of your hand. your average $30- 40 pipe in the US.