2 1/2 c. liquid starch
In a medium bowl, mix glue and one cup of the starch together. Add a few drops of food coloring, if you wish. Cover bowl, and let it stand overnight. The next day slowly stir in with a spoon 1 to 1 1/2 cups of the starch until a big blob forms. Pour off extra starch. Store in an air tight container.
(NOTE: It's hard to stop playing with this stuff.)