Onan 4000 KY valve cover gasket reusable?

Only in a pinch would I reuse a valve cover gasket unless it is silicone or other soft rubbery material. I would not reuse paper, cork or any other fibrous material. If I had to and had no other choice, I'd use the old gasket as a form to be coated with some acceptable gasket sealing material mentioned above. As MEX said, cleanliness is key.