Security is the main concern when sending a bank check. You want to make sure that the check reaches the intended recipient without being intercepted by someone who could fraudulently cash it. Fortunately, there are things you can do to increase the safety of sending bank checks.
Wrap a piece of blank paper around the check before putting it in the envelope. The piece of paper will serve as a shield if someone tries to hold the envelope up to the light to see what is inside. You can test this out yourself before you seal the envelope by holding it up to see if you can make out the check. If you can, wrap a few extra sheets of paper around it until the check is not visible.
Tape the envelope shut. Taping the envelope will not only prevent it from popping open on its own in transit, but it will also make your envelope a less attractive option to someone who wants to open mail to look for money. An envelope without tape could have opened just through wear and tear in transit, but an envelope with tape that has been opened will clearly show that someone has tampered with it.
Mail your check. Be sure to affix sufficient postage. A first-class stamp will be adequate if you are only mailing the check, but if you are unsure, the post office can weigh the envelope and confirm the cost for mailing it. You can add an extra layer of security when you mail your check by requesting delivery and/or signature confirmation or sending the check registered or certified mail. There is an additional charge for these services, but they allow you to track the check and confirm it has reached its destination. The U.S. Postal Service website has pricing information.