Good question - I just bought a boat that's been sittin' for 2 years - I gotta dispose of about 15 gallons of the stuff and have no idea what to do with it. I'll be watching this post for a good answer.
Take it to a "free" environmental cleanup collection, held once or twice a year in most areas.<br />Pay a chemical disposal company lots of money to take it off your hands.<br />Give it to someone that can dilute it and run it in their older tractor, dozer, or lawn equipment.<br /><br />Actually, with the gas prices going up, you may be able to sell it at the next stoplight.
My son, who is quite knowlegeable about things, says to add a couple of gallons to your car gas tank the next time that you fill up. Cars arn't very persnickety about it and you probably won't know the difference.
