Doooood- Try washing your glass with pure acetone and non-iodized salt, NaCl.

The acetone is a strong enough ketone to dissolve all the gunk and resinous stuff stuck in your pipe, including THC compounds, and the salt won't dissolve in the acetone so the granules can act as an abrasive cleaner. You swish it around, somtimes sticking in a HDPE or glass rod to encourage greater between the glass and the salt, and as the salt rubs off the chunks of resude, the acetone dissolves it all.
When the Acetone is black and thus saturated with resins, simply dump it into an appropriate receptacle and replace it with fresh acetone in the pipe/bong. The salt shound remain usable throughout the process. Once the pipe is totally clean. dump all the acetone into one receptacle, and the rinse the reamining salt out with water, swish it around, then pour the water/dirty salt down the drain.
At this point you can also take all the black acetone and pour it down the drain slowly with the water running on high the whole time. Water and acetone mix, so they will dilute each other-- the more slowly you pour the acetone and the more rapidly the water is running as you pour the acetone down the same drain, the more diluted it all will ultimately be.
If you want to salvage the acetone and/or the resins dissolved in it, do the following. Take the black acetone and either distill it off to re-purify it, or let it sit in a well-ventilated area where it can evaporate off. The bottom of the distillation flask or the tray used to evap. off the acetone will have a black sticky tar remaining inside of it. This is cannabis resin, and could potentially be smoked since it cetainly does have some THC in it. It certainly ain't no hash or hash oil though!

This works, but frankly it has nothing to do with any o-chem procedure involving a "reverse reaction" of THC...

--Eirias