New, genuine ivory is hard to come by these days, so most ivory items like decorations, piano keys and handles are antiques. With age and use, these old ivory pieces tend to turn yellow. If you try restoring these items to their original color using common household cleaners, you'll find yourself fighting an uphill battle. If you use bleach, you may damage the items beyond repair. But there is one old household cleaning trick that works wonders on ivory, and you don't need to go any farther than your pantry to use it.
Cut a lemon cleanly in half on a cutting board, using a sharp knife. Sprinkle some table salt onto the cut sides of each half.
Hold a lemon half in your hand and use the salted, exposed side to scrub your yellowed ivory item. Squeeze the lemon very gently as you work to release a small amount of juice. If necessary, apply more salt to the lemon as you scrub.
Set the ivory item to the side to air dry. Do not wipe away any of the juice or salt, and wait for all of the moisture to completely dry.
Soak a soft cloth in clean water and wring out the excess. Use the damp cloth to wipe down all surfaces of the ivory item. Reach into any tight cracks and crevices. When the juice and salt has all been wiped away, allow the piece to air dry.
Repeat the procedure if necessary. Even extensively yellowed ivory can be significantly whitened with just a few treatments.