Fuel Stains

Modelers, what color would AV Gas (for a C-47) appear on a NMF finish around a fuel caps? I’m assuming it would be a very light brown-yellow stain. Am I correct?

For gasoline on straight aluminum, you are correct. However, most spilled fuel attracts dust/dirt like a magnet and this turns it very dark brown, nearly black, with a very course texture.
Darwin, O.F. [alien]