Disposal after painting

Not sure this will help him but I being a painter just let it sit and let all the gunk settle to the bottom and then reuse the clean stuff on top.

I did find this online.

http://www.ehow.com/how_4532211_dispose-paint-thinner.html

That's fine ifrost but depends on what you used for thinner, xyelene or methyl ethel keytone should never be burned or evaporated. That stuff is so toxic it isn't funny, especially MEK that is some of the nastiest stuff there is, try reading the data sheets on it online. But for other alcohol, turpentine, laquer, and mineral spirit thinners you can let it evaporate or dry out and then throw it away. Same with paint itself, well not lead based but regular paint its considered a hazmat chemical when its wet even latex paint, once its dried it household trash. Do when Ifrost said let it settle pour off the clean stuff off the top and put it back in the can it came from.

I find it hard to believe that dumping 2-3 mason jars into an old cooking pan and letting it evaporate is as harmful as the millions of gallons of crap Davis Besse and others are dumping into Lake Erie.

Anyway, get an old cookie sheet pan, and set it in the sun on a picnic table outside. Dump the stuff in the pan and let it evaporate.
Or, if you want to do it like Davis Besse, take a 55 gallon drum of water, dump the mason jars in it, which will make any sample you draw from it "safe", then just dump the entire thing down the drain. Dillusion is the solution.

Hockey what crap is Davis Besse dumping into the lake? Do you mean the warmed water from their cooling towers?

Hell froze over because I agree with Liney in wondering what Hockey is smoking. The only thing Davis-Besse should be putting in the lake is warm H2O (and not the heavy stuff either!)... if anything else is going into the lake from Davis-Besse, we'd have all sorts of reports of fishermen pulling up Blinky the three-eyed fish.

Lucas County will process hazardous household waste (HHW) - including oil-based paints - for residents. Call the Lucas County Solid Waste division at 419-213-2230 for information on locations equipped to handle HHW.

Believe what you want, but Davis Besse keeps their "radioactive" waste water in a big tank for storage. When it reaches a certain level, they bring in lake water and mix it all together. That way, when they sample the new "mix" it is below the "dangerous" level. It meets the requirement and can be dumped into the lake.
So instead of dumping like 100 gallons of radioactive water directly into Lake Erie, if you mix it with 1,000 gallons of lake water, any sample is "officially" below legal limits and is just dumped into the lake.
BTW, the U.S. Navy can dump any amount of radioactive water directly into the ocean only if beyond 12 miles of land. It happens all the time.

[citation needed], hockey.