a good soak with naphtha usually does the trick, you can also soak a clean rag, and let that sit over the area to let it penetrate. You are better off getting plastic or wooden scraping tools, anything metal may slip and mar the other bits of the camera. The precut ones are easy enough, or if you want something that is unique or a covering material that no one makes you can buy the leather and cut to fit. Make sure to check the thickness of it, too thick and it will not sit flush. Book covering material comes in tons of colors and is thin and easily workable. If you can remove the covering in one piece, its easy to trace it with pencil onto the new sheet of leather, if not you can carefully measure and work slowly.