I have seen it in the grocery store as well. If you are planning to dye plastic. Heat the solution to about 190 degrees F. Then put your parts in the bath. The dye will go deeper in to the plastic or nylon. Make sure you wash the parts real well. Use a good degreaser. Do not touch the parts after cleaning with your bare handes. The oil from you hands will leave marks. If this is stuff you already know, sorry for the repeat.