What are some non-food uses for leftover egg yolks?

Question

E.g., in the categories of cleaning, gardening, beauty, crafts, etc. you can use egg yolks to...

Answer 1

After washing your hair, use them to condition your hair. Your hair will shine Also, you can make egg custard, which is very good.

Answer 2

You can mix food coloring with the egg yolks to make a fast drying finger paint for children. It's non toxic since it is food, so if they l**k their fingers it won't hurt them.