Roy's answer is good. Contact the REO agents.

A couple of suggestions: Offer a couple of different rates (not just one) depending on the amount of work the property needs. Some will be in pretty good shape, and won't need more than a regular cleaning. Others will be in shambles. And recognize that agents may not want (or want to pay) for the same level or detail of cleaning that you might provide on an occupied house. So, while you need to make sure that your jobs are profitable, be flexible on the quality and pricing standpoints.

Second, a lot of REO properties need minor repairs. Either offer that yourself (if you're able to do so), or partner with someone so that you're able to offer a turnkey package to agents with REO properties. I'm not talking about major repairs, but just minor handyman things.

Good luck.

Contact the REO agents face to face. This is a relationship business.