The locks are put on after the last collection and removed the next business day. If a box is locked, customers can use the rear slot to mail letters.

BROOKLYN (WABC) -- A Brooklyn woman wants to warn New York City residents about a potential safety concern created by the lock boxes known as "key keepers" commonly used to store spare keys for ...

The keys open lock boxes attached to the exterior walls of retail businesses, office buildings, apartment complexes, banks and the like, and are commonly referred to as "Knox-Boxes." ...

The locks are put on after the last collection and removed the next business day. If a box is locked, customers can use the rear slot to mail letters.