LOL I been doing that for years /w postage-paid envelopes but I ever thought of putting it on boxes.
My biggest problem I have is on my bus phone when I get solicited calls and its always when they call the ph is 50 ft away and I have soap to rinse off, I just put it on hold sense I have call waiting I can do that and still receive other call. If I have time its best to tell the solicited caller to take me off there calling list, by Calif. law they have to do it.
I hate the most is when those high tec solicited calls & leave msg’s on your answering machine but when you answer the call the solicited call hangs up automatically. I have to call them off the ph # from the answering machine and tell them to take me off there list if not my answering machine runs out of memory (space) from all the solicited caller msg’s! :angry