I just bought a 96 Honda Civic with a badly tinted rear window. The tinting makes everything fuzzy, distorted and dark: everytime I look in the rearview mirror I think I've developed cataracts. I peeled off a small section and the tinting layer comes off quite easily, but a layer of murky adhesive is left behind. Does anyone know a solvent that will remove this without damaging the rear window defroster?

The best way is get a razor blade and get the adhesive and tint film up and slowly pull it across so if it starts to tear you can stop the tear and get almost all of it off in one pull. After that go to walmart and in the automotive cleaning section look at the degreasers and there's some called purple power pour that into a spray bottle (do not dilute even though it says to) and spray a little on the window at a time and once it's on have a few rags to scrub off the adhesive and it'll come off with no problem did it that way on the side windows of my cherokee only instead of using rags to get it off sprayed it on and used the razor blade and scraped it off and was very easy. Walmart also sells tint remover but it's a very small spritz bottle and would take prolly 3 to get the job done.

heat gun

A heat gun won't help in taking the tint off. Installers use heat guns to help in the installation of tint to quickly work out air and water bubbles helping it to stick quicker.

Why you want to remove the tint films? There are only advantages on windows films - read this: http://www.tuningmag.net/?name=window-films-fine-tool-for-your-car