There are many ways to make slime with your kids that don't call for borax or liquid starch. Although these ingredients are not overly dangerous, they can be harsh and can cause skin reactions for some children, so try using cornstarch instead.
1. Warm the Water
Warm the water in the saucepan. Do not bring the water to a boil; it needs to be warm, but not scalding hot. The purpose of heating the water is to keep the cornstarch from clumping together.
2. Mix in the Food Coloring
Pour the heated water into the bowl and add food coloring. The color is a matter of personal choice, and a few drops are all that are necessary. Kids can get really creative here. Stir until the color is well blended. Keep in mind that the cornstarch will lighten the color, so if you want a more intense color, add more food coloring. A typical slime color is lime green, but you can choose any color your child wants.
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3. Add the Cornstarch
Add the cornstarch a little at a time, at a slow and steady pace.
4. Mix Well
Blend the mixture until smooth. It's OK to use fingers for this step. Have your child help with this mixing once the water feels cooled off enough.
5. Add More Cornstarch As Needed
Add more cornstarch slowly if the slime is too runny, or more hot water if the slime is too thick.
6. Keep the Slime Moist
When your kids are done with the slime, store it in a zip-top bag to make sure that it stays moist.
TL;DR (Too Long; Didn't Read)
Slime is a great outdoor toy. Although cornstarch slime is easier to clean up than recipes that call for borax, liquid starch or glue, it can still make quite a mess!
Because the water needs to be heated, an adult should always help children with this recipe.