I had forgot I have a couple of bottles of OSPHO already. I suppose that would do the trick. I probably need to look around and see where I can get some hose and a sprayer to apply it. I have the caps that are going on top, just figured I would want to stop the rust that is already there. Looked at some of the rust disolvers, but they pretty much require total immersion, or setting some sort of system up that can capture the liquid and then pump it back in. Of course, the problem would be the liquid does not need to be pumped in, it needs to be sprayed in to get complete coverage. I don't think my car is an isolated instance, the frame looked good on the outside but once the needle scaler broke through, there were huge chunks of rust at least 1/8" thick. Weird think about it was everywhere there was undercoating the car was good so I thought no problem. The one rail that was coated the heaviest was the worse one of all.