Originally Posted by Fabrik8

You can take off the pads and block sand the glaze off with some coarse sandpaper. You still need to go through the bedding procedure if you've got new rotors, because your fresh rotors won't have the embedded layer of friction material (from the brake pads) that they need to work well. Not the ideal thing to do, but it should work ok. Usually you're swapping new pads onto old rotors, and then you don't have to really do much as long as the pad compound is the same.