My 15Al is well-used, with a couple scratches and dings. These I can deal with. However, wiping off the palmrests weekly has not been enough to stop the aluminum from developing holes which show a black substrate (I thought the frame and case WAS aluminum, not aluminum-covered plastic). What sort of paint or other substance should I put onto the palmrests to repair the cosmetic damage? I need something thin (no plastic stick-on things that would transfer oil and dirt to the screen) that would not wear off onto my skin (most spraypaints).