Here are a few ideas:

a) Contact the acquiring institutions of failed banks. Go to the FDIC's website for the list of failed banks in your area and get the contact info for the acquiring banks and seek contracts directly that way. You need to be properly licensed and insured.
b) Contact listing realtors that specialize in foreclosures (scour your local MLS -- multiple listing service -- and find those realtors with tons of super low-priced listings to start -- these are usually foreclosures). Many of them will have their own similar companies, but they will need overflow help in this market. And, once you establish a positive rapport and they use you a few times -- and you do WHAT you say you're going to do, WHEN you say you're going to do it, they will call you again.

c) Contact larger "property preservation" companies... just GOOGLE them... usually these big companies will not be based in your city, but they will handle properties throughout U.S.

Go for it!

Cassandra, Foreclosure Cleanup, LLC

On typical bank owned or REO properties, the lising agent many times come out of pocket for trash outs, cleaning, lawn care, changing locks, etc., as this is how many agents and I do it on our REO listings. Your best bet is to market to the Realtors who handle many REO's in your area and see what they will do for you. Also another service you can do, go to your local communities HOA meetings or local HOA management companies and present yourself, and offer to cut the abandoned homes and/or the non maintained homes for a very fair price, maybe $25 a cut. Be available to them within 24 hours notice to complete and you will get some business, maybe lots. Good Luck

If I were you I would ask Trent Realty. Most of their listings are Foreclosures. Some of the banks are going in and some what rehabbing the properties before selling them, lawn care is one of the services they contract out. Also try to look for cleaning crews that work for the banks and ask them. Drive around and look for cleaning crews on recently listed foreclosure homes. Chances are the listing agent got the listing before any cleaning was done, so call the listing agent and see if they know who to call at the banks. Hope this helps.

Indian River County and St Lucie County just south of you, if indeed you are from Melbourne, Florida in Brevard County, are both discussing using this method for maintaining "abandoned" properties in addition to fines. You can contact the both counties by phone or internet. The web pages for both counties are on my website shown below.