Acid is a liquid added by Extra Bees.
-Brimstone combs are produced by Acidic Bees, which can be centrifuged to produce drops. Once placed in a squeezer, acid can be obtained. It can be transported through normal means- liquiducts, buildcraft waterproof pipes, buckets, etc- however there is a bug where the bucket is deleted upon replacement.
-Acid is a sickly green color, and has no purpose as of yet other than being decorative.