I’ve been crossing my name and USPS bar code out, circling the return address and written REFUSED - REMOVE FROM MAILING LIST - RETURN TO SENDER with an arrow pointing toward the circled return address, then dropping in the mailbox at the post office the next time I’m in the area. As to catalogs, you’ll need to contact each one individually and it takes quite a while — a couple of months or more, but it seems to work. You can also e-mail man of the catalog companies, and others have an 800 number.
Keep it coming, the postman needs the work.