AlKraut said, "Never tried this on a Contour, but it's worked on other cars:
Put your lug nuts back on, but leave them a turn or so loose. Take it off the jacks and start it up. Move it back and forth a few feet and turn wheels while moving. Jack it up, it should be loose. Good luck, and be careful!"
I know this works and was a common practice for loosening up the rear brake drums for maintenance on those "old" cars. It definitely works to free up a rim; I had to do this on my boat trailer about two weeks ago.
John
98 SVT