If I mix a color too strong I'll let it set up in the cup and put it aside. Later on when I want that color but not as strong or intense I'll cut the strong color piece into smaller pieces and add them to a couple ounces of new plastic to thin the color out. I shoot only small batches because my molds make smaller baits. If I get too much colorant in a 4 ounce batch that same batch can be used to make maybe three batches of fresh color down the road.