Miriam, your mother sounds like mine was with the plastic bags. They were a luxury!! I remember how she used to wash them out and put them over a rack to dry. She would save all of them. But then too, you have to remember they went through the depression and WW2 when things were scarce. My mother went through WW1 as well!
I don't blame your sister for praying well before meals. I think I'd do the same!