I always use transmission fluid and as small of a screwdriver as possible. Transmission fluid won't hurt the rubber. And it is slicker than most of the stuff mentioned above. I do what Mike says: Don't let the screw come all the way up and out of the pad. Leave the head hidden down under the pad when you take it off. I use transmission fuid when grinding a pad too, to keep from taking the rubber off in "chucks" and roughing up the pad. I just pour it into the cap and rub it around with my finger. Easy clean up, too.
