BLC stands for Beer Line Cleaner. Not only is BLC great for cleaning draft beer lines it is a great all around cleaner, from carboys to bottles. Because it is in a liquid from it dissolves easier than powdered cleaners.
It can also be used with cold or warm water. Use 1-2 oz per gallons for cleaning carboys or bottles. Use 1/2 oz per quart for cleaning beer lines and related parts. Because of its superior solubility BLC is the favored product for homebrewing.