Disposal of chemicals?

Private individuals and households are not bound by most state and federal environmental law because the quantities are so small. However, Chicago has some rather odd laws that do apply to private individuals, so it might be worth your while to check.

Windex and its relatives can simply be put down the drain.

Most common alcohols (isopropyl, ethyl, and denatured) you can leave out in an open container until they evaporate. The same is true of turpentine and turpentine substitute.

In many areas (this is where you have to check Chicago ordinances) it is permissible to do the same with small quantities of common solvents (mineral spirits, lacquer thinner, acetone, methyl ethyl ketone, naptha, toluene, xylene, etc.) This is often the "recommended" method. However, there is a more environmentally correct possibility—add them to used oil that will be recycled. If you don't change  your own oil, ask where you get your oil changed. Most places (in my experience) have no problem accepting as much as a pint.

Glycol and chlorinated hydrocarbons are another matter—these are (and should be) often more strictly regulated.

If it's less than an ounce by volume, I'd throw it away. 

If it's more, I generally hold onto it until I had enough to make a trip to the local hazardous waste pickup point, and then dispose of it that way (your phone book should list the location of the site, though in my experience there's only one per county, and it's typically out in the middle of nowhere; however, if you're in a suburban area, some jurisdictions will have annual pickups either at curbside or in a parking lot that's a lot closer than their established site).

The best thing to do with used thinner is to save it for re-use.  I keep a couple of large jars, the kind used for spaghetti sauce, and put my dirty thinner into it.  After a few days, the paint sediment settles into the bottom leaving clear, if somewhat colored thinner above.  After I've collected enough, I'll carefully pour off the clear thinner into the second jar.  The thinner in this jar can then be used for cleaning both airbrushes and paint brushes.  Technically, you could probably even use it to thin paint for airbrushing, although I always use new thinner for that.  Using this recycling method, I've barely used a quart of paint thinner for the past five or six years.  Not only is this environmentally friendly but cheap as well.    

ABARNE wrote:

The best thing to do with used thinner is to save it for re-use.  I keep a couple of large jars, the kind used for spaghetti sauce, and put my dirty thinner into it.  After a few days, the paint sediment settles into the bottom leaving clear, if somewhat colored thinner above.  After I've collected enough, I'll carefully pour off the clear thinner into the second jar.  The thinner in this jar can then be used for cleaning both airbrushes and paint brushes.  Technically, you could probably even use it to thin paint for airbrushing, although I always use new thinner for that.  Using this recycling method, I've barely used a quart of paint thinner for the past five or six years.  Not only is this environmentally friendly but cheap as well.

I also do this with Windex for acrylics. Some things tend not to settle out (Tamiya flatting agent, for one) so I clean those separately.

In my earlier reply, I was assuming truely "dead" thinner and sludge.

ABARNE, that is what I tend to do as well.  I haven't had to throw any chemicals out yet.  :)

However, I was wondering if it was clean enough or useful for anything but 'soaking' thinner or cleanup juice.  Obviously you wouldn't want to gun that stuff.

Chimera wrote:

ABARNE, that is what I tend to do as well.  I haven't had to throw any chemicals out yet.  :) However, I was wondering if it was clean enough or useful for anything but 'soaking' thinner or cleanup juice.  Obviously you wouldn't want to gun that stuff.

Honestly, if I didn't have any clean thinner on hand and absolutley had to airbrush something before I could get to a store, I suspect that I could use my recycled stuff for airbrushing and wouldn't know the difference.  I know while brush painting, I have sometimes thinned paint with the clear but otherwise color-stained thinner from the surface of my cleaning jar, but could see no evidence on the painted part of any sort of a color shift.  Perhaps, if one were painting pure white, but otherwise any color imparted by the stained thinner would be unnoticeable.

On the other hand, the vast majority of my thinner usage is for cleaning rather than air-brushing, so I don't feel too bad about using new thinner for airbrushing and the recycled stuff for cleaning.

I have a large glass jar (used to be pickles) with a screw on lid that I keep in a bathroom. I dump all my toxic poisons into the jar, put the lid on and leave it in the bathroom. Once in a while I leave it outdoors with the lid off and the stuff will evaporate.

It's safe to put alcohol based solvents into sewage. Compared to the alcohol that enters sewage by puking and urinating party animals your contribution is actually a tiny one and not harmful.