Registered mail is the most secure and expensive way to send a package via the U.S. Postal Service. Unless you are a jeweler, sell fine art or handle ancient documents, you probably won't send registered packages often. That doesn't mean you shouldn't know how to prepare a package and send registered through the post office. According to the USPS' website, packaging "tape must visibly damage the envelope or wrapper if removed and must absorb the ink in a postmark impression," which is why all packages must be wrapped with "plain paper or cloth tape."
Things You'll Need
Wrap fragile items with bubble wrap and tape closed so the wrap does not slide off or unwrap.
Cover the bottom of the box with about an inch of Styrofoam peanuts. Place the protected items into the box, then pour Styrofoam peanuts into the box until it is filled. This will prevent the item inside the box from being damaged.
Unroll the tape, stretch it down the length of the box and cut the tape; repeat the process so you have a piece of tape for each side of the box. The USPS won't send a package by registered mail unless all sides are covered.
Pull one piece of cut tape, adhesive side down, across the top of a wet sponge. Cover the seams of the box with the tape, making sure to smooth the tape so that it covers the top and side of the box.
Wrap tape around the box to approximate the length you will need and cut it. Wet the tape and place it around the end of the box so half of it hangs over the edge of the box. Fold the bottom half of tape in an upward motion and smooth out any wrinkles. Fold the sides in and the top down. Repeat the process on the opposite end of the box.
Measure, cut, wet and wrap the rest of the box with the registered mail tape so the entire box is covered. There should be no way to open the box without breaking the tape.