Ideas for sealing up a drafty through-wall mail slot

Pass Through Wall Mail Slots mail slot through wall The Mail Slot features an 11 in wide opening and spring-loaded front plate with an interlocking flap for tight closure It can be easily installed as a mail slot on door At Home with Lisa: Mail slots let mail in and air out One cool feature I I found a bag I can attach to the wall around the slot with Velcro It was

mail slot sleeve Mail may also be deposited in lamp boxes or wall boxes that serve the same purpose as pillar boxes but are attached to a post or set into a wall According to