How would you wash crocheted ornaments?

Try soaking them overnight in a solution of Oxyclean, detergent and hot water. Rinse them well and laid them out on a towel to dry. You will probably have to stiffen and them again with a solution of half Elmers school glue and half water. Lay them out on parchment paper or wax paper to dry, preferably in the sun. Hopefully this will work for you.

Wow, washing them may destroy the shape, especially if stiffened with glue or starch. Could you possibly clean them with a slightly damp rag and some very mild soap? If the color is an issue for you, perhaps you could spray paint them to make them white again? Good luck!

It's the glue that's yellowed. Ficher is right, they may loose their shape. If you don't want to paint them, how about embracing a yellow and gold themed Christmas tree with gold lights and additional gold and yellow accessories? Could be quite lovely.

If they are white you could just blow the dust off and spray paint them . If you wash them you will have to restiffen them.

It's not that hard to reshape and stiffen them..specially if they are two dimensional like doilies, snowflakes..

When I had an antique shop I sold lots of these. I would wash even using some bleach to get really clean. They don't have to be stiffened unless you want to use them. For storing I would not use anything. For use a strong solution of starch should do the trick.

Put them in the sun for a few days. Sunlight is the BEST thing to brighten up items that have yellowed with age.