To make homemade watercolor paints for kids you will need:
Liquid food coloring,
3 teaspoons of light corn syrup
6 tablespoons of cornstarch
6 tablespoons of baking soda
6 tablespoons of ordinary white vinegar
You will also need several small jar lids to hold the paints. Soda pop lids and foam egg cartons work great for storing paints. For larger containers of a single color, consider using peanut butter jar lids. You will be amazed by the quality of these homemade watercolor paints, and your kids will have more of the colors they use most often.
Begin by combining the cornstarch, baking soda, vinegar, and corn syrup in a bowl. It will fizz and foam at first, but when the mixture stops foaming and fizzing it can be separated into small containers to create various colors. Add as much food coloring as necessary to create the colors you want in the separate containers, and have fun mixing the food coloring to create a rainbow of paints. Allow the finished paints to dry completely, or cover the containers to keep them moist
http://www.associatedcontent.com/article/739741/homemade_watercolor_paints_for_kids.html
I didnt actually wait for the paints to completely dry so My daughter went gung ho on using them. LOL. What a mess. I highly reccomend plastic to cover your table. I got my "tablecloth" that I use at Joanns and you can get as much or as little of the plastic as you want and just using water to hose it off is all the cleanup you need to do. I hang mine on the clothes line and then spray it down, and then leave it to dry. Works well for us. LOL.
I have some of those miniture muffin pans, and I never use them so I went ahead and filled up the pans with her paint and they are currently sitting on top of my mircowave to dry. It was perfect to keep the paints in and contained. I know that if I had more then one kid trying to paint they would each need their own containers. So This idea dawned on me. For anyone with more then a single kid, try hitting the doller store for ice cube trays and then filling the trays with your newly made paints and letting them dry out a few days before you try painting with the kids. The other nice thing about the ice cube trays is that they have a flat hand holds, and just use a permamnenet marker and write the kids name on there. We hang out with a couple of ladies who are daycare providers and I thought this would be especially great for them, cause they have alot of kids they work with.
So theres something to try and enjoy! My daughter is officially in Love!