Should you use blank endorsement when sending a check in the mail?

No, it's not advisable to use a blank endorsement when sending a check in the mail. A blank endorsement, which is simply signing the back of the check, allows anyone who finds or intercepts the check to cash it. Instead, you should use a restrictive endorsement, specifying the payee's name and indicating it is for deposit only, to enhance security and ensure that only the intended recipient can cash the check.