Cover each end of a clean egg with tape.
Gently twist and press a thumbtack (or similar) into each end of the egg through the tape, creating a two small holes. Gently widen each hole to several millimeters, up to 1/8".
Working over a sink or bowl, place your mouth or a straw over the smaller hole, create a seal, and blow out the egg contents.
Rinse the egg out with warm water, and "blow out" the extra water too.
Use wire to guide a string through the egg, and tie a knot at each end - snug against the egg. Create a loop in the string on top.
Optional: use superglue to seal around the holes in the egg (to prevent further cracking) and to permanently secure the knots.
Decorate the egg as you wish, adding charms, gems, buttons, feathers, mini jingle bells, and more!