I found this on http://www.mamakenzstudio.blogspot.com/ a blog that I love to check out because she has great idea's and tips!!
Thank so much!!
4 cups water (divided)
1 cup cornstarch
In a medium saucepan, bring 3 cups water to a boil. Dissolve cornstarch in a separate bowl with 1 cup water. Remove boiling water from heat and add cornstarch mixture. Return to heat, stirring constantly. Boil until the mixture is translucent and thick (about 1 minute). Remove from heat.
As the mixture is cooling, divide into separate bowls and add food coloring. Let the child(ren) carefully mix in the coloring.
1. Add 1 tbsp of glycerin to make the mixture shiny. You can find glycerin in most drugstores or pharmacies.