On tax sale, you get a "tax deed" that supposedly wipes the title clean, but it is NOT insurable! With a county property you will get a "quit claim deed" and it likewise is not insurable. You would have to go through the quite title process in both cases to get insurable title and make sure that the banks/mortgage companies have no claim against the home. Your other option is to hold the property for 10 years. If any of the lienholders do not make any claims in that timeframe the title will become clear and insurable.
It is very important to make sure you do your due diligence and thoroughly research the title.