We have a product in the u.k. called WAXOYL.
You can buy it in handy spray cans, clear or black, use clear.

You can also get it in the U.S. - see

http://www.minimania.com/web/AddedFr.../InvDetail.cfm

See how it works here:

http://www.minimania.com/web/Item/WA.../InvDetail.cfm

Pull out the rubber seal and saturate the metal channel with WAXOYL
It will be dead easy to push the seal back again due to the nature of the product.

If you dont have a serious rust issue, e.g. holes, then this product will be an effective remedy with very little effort. (about 15mins/door)

Try it...

All the best,
Little wing