(no pun intended, and no criticism of you or OP, I think it's clever), though I was expecting more of a Sweeney Todd situation than an Acid Bath one. Still made me queasy either way.
I agree the title was a giveaway, but what do you mean more of a Sweeny Todd situation? She literally baked their blood into tea cakes that she served to the neighbourhood women and gave them soap that she made from boiling the fat of the last victim... Also, it's a little pedantic, but I believe that technically she didn't dissolve them in acid but in a strong base... If it was from soap making, it was most likely lye which is extremely basic. Caustic just means it will dissolve you, but both acids and bases can do that.
She ended up in the pot, like the other two... her flesh was fat and white, when it had melted I added a bottle of cologne, and after a long time on the boil I was able to make some most acceptable creamy soap. I gave bars to neighbours and acquaintances. The cakes, too, were better: that woman was really sweet.