Disfigured Old Woman With Club-Foot Kills Guests in Mansion

by Claude Lebaron
(Quebec, Canada)

Dear horror expert(s),

I am looking for the title of a horror movie that scared the nightlights out of me as a kid about two elderly sisters living in an old, creepy mansion.

One of them falls into a container filled with powdery lime and gets badly (and I mean badly) disfigured. Becoming crazier and crazier with the chemicals that are eating at her brain, she goes around killing a bunch of guests in the house.

As she's doing this, the guests can hear the bone-chilling and ominous sound of her club foot dragging toward them.

Thanks for your help! Happy nightmares all.