It is true. I shred those bulk mailings, but I was referencing the many Junk but non-bulk class letters I receive. It makes no sense to write return to sender

It is true. I shred those bulk mailings, but I was referencing the many Junk but non-bulk class letters I receive. It makes no sense to write return to sender on a bulk-mailer. While much Junk mail is sent via bulk rate, Junk in this context refers to the content not to the mailing class of bulk.