I've always been sensitive to poison ivy, so I'm on the lookout for it when in the bushes. I used to use Tide powdered laundry detergent to wash when I got in it. The granules added a scrubbing action, and the Tide seemed to work. I suppose any other powdered laundry detergent would work as well. I haven't used Dawn, but it would probably work as well because it's the same principle of oil removal.
