If it's not lunched too bad you can just resurface it. Tape a pice of fine sandpaper to a thick piece of glass (my dining room tabe worked nicely). Wet it with WD-40 and sand the cover in figure 8 patterns taking care to apply even light pressure so you don't sand the leading edges in the direction you are moving. I've done this numerous times on the same cover and it always puts a nice fresh surface on it.