Make the letters very short w/o any threats or formalities e.g.

Someone who knows your business and who will be loyal due to the amount of work you provide, and can assist you with evictions as well as other matters (zoning, contracts, small claims suits, general advice, sending threatening letters to people you don't like, etc.).

I sent the appeal with a copy of the sales contract and appraisal, and they simply sent me back a letter saying they dropped it to my requested value of 80k.

That doesn't mean you are necessarily going to kick them out, but they need to know that if rent is late, you're calling to ask about it, sending them a demand letter, and promptly filing an eviction.  

This deal was first constructed by driving for dollars and sending out letters by hand.

Ask the neighbors, leave a note on the door, look up the probate records if there are any and contact the attorney and the executor....look up obituary and skip trace the relatives, send a letter to the property and see if it gets forwarded to anyone.  

Hand written letters have been truly effective for me. 10% response rate.

Hi @Pete Fiannaca,When a mortgage underwriter needs clarification about the way something appears on your tax returns, a human accountant will write that letter.

Hello All,I recently sent out a slew of yellow-letters and received a call back from a gentleman that wants to get rid of his two properties.

I could send out a lot of letters writing them myself with that, and it would only take 1 deal to make it worth it.