Magical Pixie or Sleeping Dust
Every child I have ever known has loved anything magical. This magical sand is no exception. This has many uses and can be changed to fit your needs. The labels here are for a sleeping dust that you could use on Christmas Eve, on Tooth Fairy nights, or for a party as Magical pixie dust. Just change the labels as needed.
If you are using multiple jars like this give each child a ziploc bag or another container and then give them a bit of each as you would like and have them mix it all together to make whatever magical potion you'll be making.