I have seen some people get REAL messed up huffing Toluene. Be careful, that stuff is toxic.
I use Simple Green. Works great, and is environmentally friendly. It definitly cleans everything off the gun, not leaving any bit of grease oil or dirt. Of course, I don't think it will work as a bore cleaner (?). Try it, you'll like it. It is cheap too: one $7 jug will last many many years, and you can use it as a househuold cleaner as well.