I am just about finished with both wings and when I was assembling the fuel tank I noticed the ribs were not shiny aluminum but had a very slight green tint (almost clear). I know from other postings to be sure the ribs are clean clean clean before getting to the proseal phase. I spent considerable time with acetone removing the coating on the tank ribs and the ribs now look nice and clean. The question is, is it normal to have coated tank ribs or did I just remove something that shouldn't have been removed? These ribs haven't been touched in 10 years and perhaps back then Vans put some kind of near-clear primer on everything.