If you can get them to send you a solicitation through the mail with a prepaid return postage envelope, do so. Then tape the envelope to a brick and let them pay the postage. Be sure to include instructions for them to place it where the sun don’t shine!
A fellow Freeper pointed out to me that the Democrats will cross check you. You can claim to be a Democrat, but are you getting the NRA magazine? Who did you donate money to? You donate money to right to life groups? No need to send Democrat mail to you.