If you mean that you are interested in buying homes that are being sold for the the past taxes due. Each state and then some counties have different rules. California, you can go to the County Tax Assessors website and they will list the procedure and location of auctions in their county. In Texas, the procedure is much easier. They sell properties much more quickly than California. Check the County Tax Assessor website or call them to find out what the procedure is for that specific county. Best of luck, be persistent.