Trying to sell antique ivory piano keys from 1905?

I would refer you to a question about ivory

https://www.askmehelpdesk.com/crafts/can-sell-ivory-piano-keys-392315.html

I know that ivory is illegal after a certain years but I really don't know what that year is there anyway you know that year and where I could sell these keys?

I have found a dozen or so dealers or sales on eBay,
I also found a few on craigs list.

Depending on condition, some piano restore companies may want them.