My name is John Doe, I am an Investor in [Your City] and I would like to discuss with you the purchase of your property at 123 Memory Lane. I am a very serious buyer, so if you would like to sell please give me a call so we can work out a deal that will work for both of us. You can reach me at (xxx)-xxx-xxxx.
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Best is to use the yellow letter marketing concept. Hand written letter, hand addressed envelope, live stamp, return address but no return name.