Originally posted by HSE2
I am not expert but I always thought that the old mags were gathered up and taken back.
Depends on the publisher, etc. When the mother-in-law used to work in a Newsagency it was often only the front cover that would be torn off and returned to the publisher as proof of NO-SALE to issue a refund to the agency. The rest of the mag(s) would go in the industrial bin out the back.
I scored a lot of free month-old auto mags that way (minus the front covers). Ssssh! don't tell anyone.