READ THIS NEXT: USPS Warns All Americans Must Do This to Keep Their Mail Safe. The USPS has been handling our mail for quite some time, dating all the way back to 1775, and there’s a certain level of trust we have in the agency to get it right. But there have been plenty of bumps in the road. Just last month, the USPS issued a warning about increasing mail theft. Criminals have been pilfering mail from mailboxes, and some have even stockpiled sensitive documents and property. In June, the North Precinct for the Portland Police Bureau (PPB), in Portland, Oregon, located a “plethora of suspected stolen property” during a warrant search of a local home. According to a tweet from PPB North Precinct, items had been stolen from over 30 victims, including social security cards, passports, and even an official USPS jacket and hat.ae0fcc31ae342fd3a1346ebb1f342fcb Unfortunately, these thefts are far from an isolated problem. Now, another police department is asking that you reconsider mailing one particular item. When you write and send a check, you should monitor your bank account to see when funds are withdrawn. If you see an amount nowhere near what you wrote the check out for—especially a sum that’s considerably larger—it might indicate that you’re a victim of “check washing.” This fraudulent act is carried out when a thief changes the amount you wrote on your check and then deposits it. As part of check washing schemes, thieves will “wash” the check in chemicals in order to remove the ink you wrote with, according to the United States Postal Inspection Service (USPIS), and some will also print fake copies of the check with the help of copiers and scanners. If you’re scratching your head, wondering how they got their hands on your check, it could be directly from your mailbox, the Sebastian Police Department (SPD) in Florida warned on Aug. 1. According to a Facebook post from the SPD, the department is investigating several cases of check washing, and urging residents to be mindful when mailing checks out. “We are warning our residents to be extra cautious when placing any type of check in your residential or commercial mailboxes to be sent out by the U.S. Postal Service,” the post reads. RELATED: For more up-to-date information, sign up for our daily newsletter. The USPIS is aware of the uptick in check washing, as well as mail theft in general, and the agency has an entire Fraud Complaint System that keeps track of incidents. The problem is only becoming more widespread. In addition to the washed checks discovered by the SPD, the PPB North Precinct in Oregon also found washed checks during their search. Thieves are stealing from all kinds of mailboxes, and in July, mail theft was an issue with USPS Blue Collection boxes. These boxes were being targeted by thieves actively looking for checks, and several senators even sent an urgent letter to the U.S. Postmaster General regarding the thefts, stating that Americans “should not have to worry” that their tax or bill payments are being stolen. According to the USPIS, postal inspectors recover over $1 billion annually in counterfeit checks and money orders. If you suspect that you are a victim of check washing or mail theft, contact your local authorities to file an official report. But to avoid having to get the authorities involved or put your financial security in danger, take precautions to protect yourself from check washing schemes. The USPIS suggests three key strategies. First, avoid leaving your mail in your mailbox overnight—leaving it unattended simply puts it at higher risk. In terms of incoming mail in particular, you can put your mail on hold at your local post office if you’re going to be out of town for an extended period of time. You can also ask a trusted friend or neighbor to pick it up for you daily while you’re gone. Lastly, if you’re going to use one of the blue collection boxes, the USPIS recommends that you drop off mail just before the last pickup of the day. You can find pickup times and days listed online, at the post office, or on the physical collection box.