I'm afraid I'm just not willing to invest that much time in costing them money--because the amount of money it costs the sender is significantly lower than the value I put on my time. Sure, if enough people do it, they will eventually find it unprofitable to send their junk...but the human resources wasted in getting to that point is overwhelming. Maybe I should hire a neighborhood kid to come by weekly, for envelope stuffing. $5 per week might be worth it.