In the "Cat's in the Bag..." episode of Season 1 of "Breaking Bad," characters are shown with 4 gallon-jugs of Hydrofluoric Acid that they use to dissolve 2 adult corpses. Chemistry is a major plot device in the show and it seems like they go to some effort to keep those elements based in reality.
According to this article, hydrofluoric acid is a good choice for your body-melting needs. But if a bath is usually around 200 liters (50 gallons), could you really do it with just a few (5-10 liters, 2-4 gallons) of acid?
It's worth pointing out that for the purposes of this question, "dissolve" is defined as "creating a toilet-flushable slurry."