Hey -- I started to have the same problem w/ my 'tour, I ended up using this bondo ruberizer in my wheel wells and around the lip it seems to have slowed the problem quite a bit. You get the the stuff from canadian tire for about 10 bucks. Of course this is a preventitive move...
As a sight aside, any recomendations on where to get your car rustproofed? I heard the Krown is pretty good, however is it worth the extra dollars?
Contour 95' LX V6 120K
Stock to the block
Acura CL 00' 80K
Equally as stock to the block.