If you do not want to use chemical strippers,pressure washers, or sand blasting there is one more option at hand that I know of for concrete. It is an air tool called a Needle Scaler or for larger jobs an air tool called a Scrabler these tools are very handy for removing paint rust and every other thing from concrete, metal ect. Alot of pnuematic tool manufactures carry them but if you are only going to use this tool for one job the best price I found was from Northern Tool and Equipment.