Fee's for clearing out squirrels and other pests

You may be able to hook up with a local licensed exterminator or 2 in your area. Depending on local laws, you would probably be covered by his liability insurance. Let the exterminator charge the customer, then take your cut based on time, pests, or whatever you agree upon.

I'm betting this type of pest control is too time consuming and specialized for most exterminators, so they may be glad to have your services.