If you have something that you absolutely want to make sure it gets to where its going via USPS, then ship it registered mail.
Yes, it costs more, but there is 100% accountability from your hands to the receiver. Every person who touches a "red" has to sign for it and accept it. If it's lost, the USPS knows exactly who to ask about it. It doesn't flow with the normal mail stream and truly does get special handling.
But, you're going to pay for it.
