It depends on the piece.
I put mine in the dishwasher, knowing that the glass they are made of is dishwasher safe. I run it at warm, not hot, temps, and don't use the pots n pans setting.
The water pipes never come quite clean that way because the dish soap is not the correct solvent for the resin buildup (salt + alcohol is indeed a better choice), but it is a quick thing that I can do a couple times a week when I happen to be running the dishes anyway, and it really keeps that stale-bong smell in check.