The Clay County, Missouri, Sheriff's Office is issuing a warning to anyone with important mail to send out — you might want to make a run to the post office first. Deputies are seeing an uptick in the theft of outgoing mail, according to a post on the department's Facebook page.Those thefts tend to lead to personal checks being "washed," then rewritten and fraudulently cashed. "As convenient as it may be to use your home mailbox for outgoing mail, we encourage you to instead use the U.S. Postal Service's blue mail boxes at Post Offices and around the community to ensure your mail is delivered securely," officials said in the post. Officials also said if it's a matter of paying bills, most can also be paid securely online or through your bank.