An ad on Craigslist will get rid of all of your used oil, as long as it's not contaminated with water, or antifreeze. When heating my other shop, I burned on average of 350-400 gallons a year. I kept the shop @ 50º, then bumped it up to what was comfortable, for whatever I was doing. Mine will burn anything from brake fluid, to 50 wt.
It's just a shame it won't burn jet fuel. I have a source that when they inspect their crafts fuel tanks, they have to be purged, and fuel disposed of. I'd never have to worry about a fuel supply if it did...
If you have a corner to set a barrel, and dump your used oil in, when it's full, post the ad. Guys like me that burn it will either provide another good barrel, or bring it back if you're close enough.