MELTING KEY MAGIC TRICK

The Magician takes a standard blank (uncut) key and it is shown front and back. With a rubbing stroke of the forefinger, makes the key notches magically cut. The key can be passed out both before and after the performance.

A common cutting (tooth) bearing no keys ,before performing inspection can be handed over to the audience, then borrowed from the audience in a key, the magician can according to the key of the audience with his fingers directly copy the key indented to original keys, cutting and tooth, same become good grinding(toothed) keys can be handed over to the audience after the inspection.
The magic is simply a miracle of visibility.
An organ props, a total of three keys!