How to Color Slime
No matter what base you use—clear glue or white glue—sometimes slime just doesn’t turn out the way you want. Here at Ruffles and Rain Boots, we make a lot of slime, so we can attest to that.
To balance the white glue in slime, you need to add a ton of food coloring. Conversely, when using the clear, the colors aren’t vibrant.
Most people use food coloring, which is acceptable because both gel and liquid colorants are effective. However, there is a trick: soap coloring! Because it is contact-safe, even children can play with it.
Pick up an inexpensive pack of soap colorant if you (or the kids love making slime). We used it for this ladybug slime and WOW – it’s impressive in person!
Adding Color to Pre-Made Slime
Community Answer Its a laundry additive that stiffens fibers and prevents wrinkles. Youll find it in stores alongside laundry detergent and dryer sheets. Community Answer You could wear gloves, but you could also add tiny bits at a time, to reduce how much you get on your hands. 
T. Chinsen Top Answerer In the Things Youll Need section of the article, eye shadow is listed as an option to powdered pigment paint as a colorant. Your choice depends on the amount of slime being made and the level of color desired. Powdered paint may be more economical if a large amount of slime is needed. Eye shadow may provide unusual colors that cannot be made with paint powder. Also, Do You Know How do you dye slime with food coloring?
Once the glue and water are thoroughly blended, add a few drops of food coloring to achieve the desired shade. Next, stir in the liquid starch as the mixture turns into a blob. The slime might need to be kneaded for several minutes in order to achieve the desired elasticity.
Generally speaking, most people use food coloring, which is fine – gel or liquid colorants both work well. Check out our Amazon shop for the best slime ingredients, entertaining add-ins, and colorings.