Neil,
I haven’t done it either, but I’ve thought about it. It sounds like a good idea.
Here is another idea to consider. If you are regularly preparing letters to mail anyway, take a few with you each day and leave 4 – 5 at the neighbors of each home you clean. This is sometimes called 5-arounds. You can get some clear plastics bags that are intended to be hung on doors and slip the letters into them. You might need to tweak the wording of the letter slightly to say “you were in the neighborhood working” rather than read like a cold call mailing from your office. You could leave a small space on the letter and write the address you worked at. Perhaps include a small discount offer. I would think the majority of the letter could remain the same as the ones you will mail.
The 5-arounds idea has been discussed a couple of times on this board. I believe the few who did it received a decent response. You don’t need much of a reply to have a nice ROI because the cost is so little.
I’ve done it some and gotten work from them.
The beauty of it is that each person receiving the 5-around letter can check with your customer and remove any doubt about your quality of work. They end up hearing a testimonial.
If you have 2 – 3 jobs per day, this could put your letter in the hands of 10 – 15 more people and save you the postage. It only takes about 5 extra minutes at each location.
One note of caution. Some people are very private, so I usually just write the address I worked at and not the customer’s name.
Good luck with your idea!
Mike