My favorite backpack is 10 years old, but it was still going strong until recently. I stored it at my parents house when I moved out of state. My dad tossed it up in the attic with his old backpacking gear, and now it is sticky on the inside (I'm guessing it's the waterproof coating breaking down). It doesn't have an odor, or any mold or mildew smell. It's just sticky. Is there a way to get rid of the stickiness or scrape off the old coating?

The bag is in perfect condition otherwise since I was careful to take care of it. I really can't afford to buy a new backpack.