Cleaning your rims might solve the problem. If so, it's likely that you will have to clean your rims regularly to keep the problem from coming back. Switching brands of brake pads may or may not solve the problem.
Often the root of the problem, when this happens, is that the bike has been ridden with low tire pressure, and the rider hit a bump, bottomed out the tire, and dented the rim. If that's true there is no way to take the dent out of the rim.