B.D.
Tie it to a balloon and let it fly away to another child.
Put it under a pillow and let the fairy take it for another child.
Give it to a friend with a baby (just make sure the other mom knows what you are doing)
Put it in a memory box for the child
Dig a hole in the yard and cover it with dirt, the child will love to dig!
These are just some ideas my friends and I have used with our kids!