I was reminded of this project by Adventure of Bear.
We used: Borax (in the laundry section), boiling water, pipe cleaners, wide mouth jars, yarn, butter knife and scissors.
Cut the pipe cleaners and shape like snowflakes. Any shape will turn out cool. No 2 snowflakes are alike. The snowflake needs to be able to fit in the jar.
Tie yarn onto snowflake and rap the other end of the yarn to the butter knife for when you place it in the jar.