Best bet is to take the "pad" off, should easily come off with rubbing alcohol and some paper towel, just dont use Kleenex tissue, as it is really linty in nature. Also maybe getting some 1500 or more grit sandpaper to "buff" the surface.
Get some decent thermal grease, i like the old Radio Shack stuff, but most of the people on here swear by Arctic Silver 2. I have done tests and shows the AS2 is over rated, especially for the price, but if you cant get the old Radio Shack stuff, get AS2 as it seems to be better than the new Radio Shack stuff.