Is it possible to soundproof a door with a mail slot?

Mail Slot Insulation - mail slot insulation insulating rubber seal that blocks drafts and an interior brush strip for greater insulation and privacy This mail slot won't rust or tarnish Its flaps mailbox slot cover I used foam weatherstrip tape with the adhesive backing It's not fully airtight, but much better than previously, and the mail slot still

mail drop slot Plumbing & Pipe Insulation · Window & Door Screens · View All Products · PDF Mail Slot – 13″ Aluminum mail slots from M-D Building Products are durable