The United States Postal Service makes mailing things easy thanks to over 130,000 blue USPS mailboxes across the country. However, the USPS has issued a warning to residents who plan to use the collection bins, explaining that they might not be the safest option.

A press release that came from an unnamed postal inspection office states that the blue mailboxes have become very attractive to thieves hoping to steal checks or identities, especially at specific times and on specific days. The agency said, "The biggest variable enticing these criminals to steal are customers depositing mail into blue collection boxes after the last collection of the day or during Sundays and federal holidays."

The USPS has some advice to protect customers wanting to use their services. They explained, "If customers simply used retail service or inside wall drop slots to send their U.S. Mail, instead of depositing it to sit outside overnight or through the weekend, blue collection boxes would not be as enticing after business hours to mail thieves for identity theft and check-washing schemes."

In a list of tips, they also suggest, "The most secure way to send mail is through the local Post Office retail counter. If that is not feasible, the next safest way is to use the inside collection slots that deposit mail directly into the Post Office. If using the Postal Service’s outside blue collection boxes, never deposit mail after the last dispatch time. Each box has dispatch times printed on a label, and it will point you to the location for the latest pickup time in your area. Avoid depositing mail during the night, Sundays, and federal holidays."

If you ever pass by one of the blue mailboxes and notice someone who doesn't look like a postal employee rummaging through it, especially during non-postal work hours, the USPS asks that you report it to your local police or call the postal inspectors at 877-876-2455. Your good deed will even be rewarded. To incentivize people to call in suspicious activity and help curb mail theft, the USPS is offering rewards of up to $10,000 to anyone whose tip helps catch a thief.

Joel C. Rosenberg is a New York Times bestselling author of 13 novels and five nonfiction books, with nearly 5 million copies in print.