In this trick, you can make an ordinary coin seem to disappear in a handkerchief. Borrow a coin from your audience member and place it under the center of a handkerchief. Ask a volunteer to hold the coin under the handkerchief, then jerk the handkerchief away. The coin disappears.
The trick in this is in the handkerchief. Buy two identical handkerchiefs. Cut a large triangle of the corner off one. The corner must be bigger than the coin you will use. Sew the triangle onto the corner of another handkerchief, sewing a coin into it, so there is a coin trapped in the corner. Make sure the volunteer's coin is similar in size to the one sewn into the handkerchief.
As you cover the volunteer's coin with the handkerchief, make sure you pull the corner of the handkerchief to the middle of it, so the hidden coin is right over the real coin. With your other hand, lift the covered false coin a little bit, while quickly concealing the real coin in your right hand.
To hide the real coin, press it against your palm using one or more of your fingers. Or try wedging it casually between two fingers.
Once you have the coin in your hand, you need to hide it. While the volunteer is holding the concealed handkerchief coin, pick up a magic wand on the a desk and drop the real coin there. Or, act as though you have to get magic dust out of your pocket, then drop the real coin in.
Finally, say a few magic words and yank the trick handkerchief from the volunteer. They will be amazed to see that the coin has disappeared.
To make the coin reappear, you will have to retrieve it. Instead of dropping it as demonstrated above, you may want to keep it in your hand the whole time.
Or you can use the act of pocketing the handkerchief to retrieve the coin. Hide it, again, pressed against your palm, then put your hand behind the volunteer's ear, or any other surprising place, and push it to the tips of your fingers, making it reappear.