exhaust stains??

i have some brownish stains directly above my tailpipe, lol, that wouldn't come off with car wash soap and vigorous scrubbing. anyone else have this problem?? i can't really get a good picture of it, but it's there. i wonder if i'm running rich or what.

 

I had this mark on my truck buying it second hand. I think it's more of just being warm and it "bakes" the dirt onto the truck. I took my meguiars buffer and a little compound and it comes right off

 

ok, i appreciate the tip. i'll get some compound to get it off. i have been letting it warm up in the morning lately since it's cold out so that's probably what it's from.