I would market yourself to the entire area. If you stick to just REO, you may miss Realtors who specialize in Short Sales that often need cleaning and preservation. Look for an easy cost marketing. There are many e-flyer companies that you can use. Many will email to all the Realtors in your area with just one click and a small charge from $10 - $20. Place your services in the ad and more importantly highlight your cost. Maybe run a limited time promotion to get people motivated to act now. Then, do the best service ever. I know if someone does great service for me, I will tell all my Realtor friends. Word-of-mouth is the ticket.
As far as your advertising, make sure you do it at least 5-6 times in the beginning to the same agents. Once won't do. Studies show it takes at least 5 viewings before you start to stick in peoples head. Make sure you have something that stands out so you will be remembered.
Best of luck.