Those envelopes hit the recycle bin and never make it into the house. I mean, really!? Do they really believe anyone is still falling for that BS?
I send them back in their prepaid envelopes, devoid of any comments or money. Sometimes I just send the envelope empty. When I received the same from the Party and the RNSC during the 2010 cycle, I just printed off several copies of my Rubio bumper sticker and sent that back to them, on their dime mind you.