I am aware of the gouging the agencies do and believe it is wrong but they are a necessity for me to help keep bookings coming in.  Instead of making them for the agencies I would make them for the property managers and go around and speak with them.  I know mine always wants to know of great cleaners to pass along to the home owners.  As an example.....I thought I had the best cleaner ever available.  Then I see her  mug shot on the Internet a few months later for theft!!!!!   I had to go to my Property Manager and ask who would she suggest that I use and now have one that is perfect for me.  You can also look up the property appraisers site for each county and get the owners address to then send them a letter.  I can not say that this would work well either and keep coming back to visiting the Property Managers.