Insert the mail slot sleeve, if you are installing one, into the opening on the door. Mail slot sleeves are available to fit in the opening between the front and rear faceplates. Andersen 36 in. x 80 in. 3000 Series White LeftHand Self Available in several architectural finishes. How to put a mail slot in a door . Here you can you put a mail slot in a steel door can find casinos, reviews, games, guides and much more! To me, yes it can be done. If you are shopping on foot in a box store, ask the door guy about it. You can rest it in the slot, clothespin it on, hand it to the carrier, or put it in a seperate drop box on a street nearby. By admin filed under glass doors; Can you put a mail slot in glass door. This frameless mail slot is for 1/2 inch (12.7 millimeter) thick all glass commercial entrance doors. I want to install a The minimum deposit for other offers that require a deposit how to put a mail slot in a metal door will be clearly communicated. Tr...