I used a sign last winter when I injured my back - sliding off a roof is one of the parts of my job I hate most. The sign, just a small sheet of white paper against a white door, so as not to attract attention, said "I have injured my back and cannot answer the door. Phone me and leave a message and when I can get to the phone, I'll ring you back." It worked so well, I left it up for the usual spring onslaught of canvassing.

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