Sorry for the vague title, but was not too sure on what to call it.  Anyways, I am redoing an old control line model I acquired a few years ago.  I sanded it all down with 120 quickly then 320.  It is just where the old fuel tank was mounted is giving me a little problem.  The model finish did not seem soft before starting, but now while sanding, it feels 'rubbery' in mainly that area.  The best way to describe it would be gooey epoxy.  It does not appear to be fuel soaked.  So, I was wondering if anyone may know what I am facing here and any possible help as to how to repair this.  ANy help would be greatly appreciated.  Thank you.

              I've used K2R spot remover sprayed directly on the balsa. While some on here claim that it works wonders, it takes repeated applications. I would follow with a wash of thinner. I would spray again and again. This was on a full size stunter. I would imagine something smaller certainly wouldn't be as bad. I would have to place paper towels on the surface over the dried K2R and iron it and the heat would further draw the oil out of the wood followed by an additional application again. K2R goes on in a liquid like state drying to a fluffy powder. It stinks and it shouldn't be done inside. The ironing with the towel equally stinks. Ask yourself if you really love this plane. The end result isn't going to be as perfect as one would like. You will get it into a useable state but it might be easier to rebuild. In addition, K2R is a bit pricey and has been relatively hard to find. I believe others have used corn starch mixed with thinner or acetone possibly even alcohol mixed into a paste and applied to the surface. It just seems like the oil becomes never ending and tends to resurface. Ken