People sending mail or packages will want to pay close attention to pick-up times when using large blue collection boxes.
An official with the United States Postal Inspection Service (USPIS) says criminals may target blue collection boxes after the last collection of the day or during Sundays and federal holidays.
The USPIS recommends that people deposit outgoing mail before the final pick-up of the day, so it doesn't sit in the box overnight or through the weekend.
If the final pick-up has already occurred, customers are encouraged to use the letter slots inside their local post office's actual building. They can also hand the letter or package to their carrier.
USPIS says the U.S. mail system is still one of the "safest and most trusted ways to send gifts and greetings to friends and loved ones."
Customers can sign up for informed delivery through the postal service to get a better idea of when their mail is delivered.
Editors note: This story clarifies that the USPIS says people should be aware of final pick-up times at blue boxes, not avoid them altogether.