Rescue a Balloon with a Helium Transfusion

Step 2 Drill for Helium

Most "mylar" helium balloons have a built-in one-way valve that consists of a flat tube of plastic that extends into the body of the balloon. Gas flowing in expands the tube and has no problems. Gas trying to get out tends to collapse the tube, so no passages is possible. It works really well. Some balloons have an additional self-adhesive layer to seal the tube shut, in which case you may be out of luck.

Find the opening for the inflation value on the step (usually) of the sacrificial balloon, and shove one and of your transfusion tube gently through the valve-stem until it escapes the far (internal) opening of the valve. This is usually 6 to 10 inches. Now your tube is holding the valve open, and helium can escape through the tube (You should be able to feel some if you squeeze the balloon.)