Open a rich looking small wooden box and remove a square of glass.

Pass for examination, if you must.

Onlookers see a wooden box with a slot in the top and the bottom. It looks like it is big enough for a coin to fit thru. But wait, if I put this square of glass in the box it blocks up the holes. But now I have a neat magic trick.
I’ll get a coin to penetrate right thru the glass right in front of any spectators eyes.
 

That’s just what happens.
The spectators can see the coin literally melt right thru the glass with the box held at eye level.
A helper catches the coin as it falls out. Box is opened and the glass is intact. So is your reputation.

This box, beautifully crafted in teak wood, is used for a highly effective penetration of solid through solid.

The performer displays a small wooden box with slots on top and bottom through which a coin can pass. A glass sheet is placed inside the box.

It seems impossible for the coin to pass through the box unless it penetrates the glass sheet, yet the performer manages to do just that.