If theres no rust a light wet and dry sand will be required to get the new paint to stick propperly. If there is rust id take it right back with a grinder+wire brush wheel. If it has any stickers that need taking off make sure that the silicone glue is removed absolutely completely then wipe the rims over with thinners before repainting. If you do have to take it right back because of rust use an under coat. A 1600 wet and dry between coats will give the best finish. Use Acryllic paint its cheaper and does the job fine. If you want a super glossy finish after the last coat goes on give them a good buff
Cheers Chris