Here is what I do for mailed political or money solicitations that have a stamped enclosure. I take every piece of paper... ads, solicitations, etc... that does not have my name on it, stuff it in the envelope and mail it back to them.
If you know anyone that lives in his district and gets a prepaid envelope from him, tell them to do that. It wastes the time of his staff and annoys the hell out of them. If one wants to waste the price of a stamp, one can do the same thing. Nothing illegal about it. The most that would happen is the Post Office would send you a letter telling you to stop it.
