Unscrew the cap of the glue bottle and pour out all the glue into the medium mixing bowl. Add 8 oz. of warm water to the glue and stir well.
Add 2 to 3 drops of desired food coloring to the diluted glue and stir well with the spoon.
Place the remaining 8 oz. of warm water into the small bowl and add the Borax to the water. Stir the liquid until the Borax dissolves.
Pour the Borax solution into the diluted glue slowly, stirring while you pour. Continue pouring and mixing until you add the Borax solution completely.
Knead the Gak mixture with your hands until it reaches a smooth and supple consistency -- a minute or two at the most.
Place the Gak into the plastic container and cover the container tightly with the lid. Store the Gak at room temperature.