Or give it to the dog and have the extra entertainment of watching him try to get it off the roof of his mouth...good time.
We stick them in the sink with some soapy water and let it soak for awhile, then put the lid back on and shake it. It does come out.
We recycle just about everything we can, but there are a few things I just toss and won't mess with to recycle, like chili cans. The greasy chili residue is pretty hard to get out without using so much water that I can't really see that as being particularly helpful in the grand scheme of things (and I'm not going to shove my hand in there to scrub it out and cut myself on the tag where the can opener didn't perfectly cut through). But of course that's just my opinion...