This black ABS regrind is used for attaching ABS fittings to ABS holding tanks. Typically, take an old glass jar and mix one part of regrind to two parts acetone. Let sit overnight. Use the slurry to glue your parts together. This forms a far stronger bond than using pipe cement. Regrind comes free with our black tanks. You will receive 1/4 pound of regrind. That is enough to install several fittings.