I get letters like this sometimes (people looking to buy either in our area or specifically our house). This only works when you personalize your letter to the

I get letters like this sometimes (people looking to buy either in our area or specifically our house). This only works when you personalize your letter to the specific house, and sell yourself - i.e. not send a generic 'call me if you want to sell', because then people will assume you're a realtor. I don't think this can be made into a service - it only works when you're clearly not a business and when you can show that you've put in the effort.