If you would like to get into the foreclosuyre cleaning business the 1 thing that most banks will ask for is insurance. Depending on state laws where you live, you may or may not have to register as a business. You should have business cards, have a loist of what services you can provide and what the costs of them will be.
I would start in your local area by visiting the listing agents who specialize in bank owned homes, offer free estimates, same day service for them and offer prices just below market value. if you get the jobs do a good job and you will get repeat business.
i have a whole blog with tips on what to do and what not to do.
please check it out