We used hose water and Johnson's Baby shampoo (fittingly it said, 'No More Tears' on the bottle) to get rid of the stuff. From what I'm told, that's what seems to work the best.

I'm not sure if OC spray uses some kind of oil base, but that's what it felt like. It's extremely difficult to remove completely. Next time I took a shower, after getting sprayed, it actually reactivated it enough to be quite unpleasant.