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Mix the two together. May turn purple overnight if you use the wrong detergent. A ratio of about 1-1.5 tsp of food coloring to 1/3 cup of detergent seems to work pretty well, but try out different amounts to see what works best.
Note: it is more cost effective to buy a large bottle of food dye online than multiple of the small bottles from shaw's if the show will require multiple of these. 2/3 cup detergent and 1/2 to 1 tsp food dye is an okay ratio to start with, but try it out with the particular ingredients used and adjust to match preferences.
Type 3 - Commercial
Advantages and Disadvantages (Grace Kane)
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