Re: Plugging front door mail slot
Unless you have some fairly substantial woodworking skills and at least a basic set of tools, there is nothing you can do to make it disappear. Even then, with seasonal expansion and contraction, the patch will likely crack and be visible in short order anyway.
You could leave the slot there, which won't change the aesthetics of the door, and fill the void with foam rubber that you can buy from a craft or fabric store.
I suffer from CDO ... Its like OCD, but in alphabetical order, LIKE IT SHOULD BE!!!