You don't need to sand them. If you have a bench grider just get the buffing wheels and do it yourself. Try to get as large a wheel as possible (10" or 11"). This will reduce your effort and also get a better shine. I bought some through Caswell (they are on the internet, but I don't have their info anymore). You can also buy the wheels at Sears, but they only have the smaller ones. There are different waxes to use and they can be bought at Sears or wherever you get your wheels. If you don't want to spend the time or money getting materials, take them to a chroming shop. They are pretty reasonable and can actually do a better job. I had a shop do the trim around the rear window and it looks brand new. They can also straighten them and take out the dings.