White spirit on the rim and clean it off with water. Then sand the pads down. But to be honest though. Your best option would be a re-grind. Sure, the white spirit will work, But probably not as wel as a nice grind. Just grind the rim and make sure the surface of the pads are clean(Sand them down, Then get a new bit of sand paper and do it again. To make sure theres no oil on the sandpaper you were using to begin with) Then just set it up and get going.