During WWII, my mother ran out of cooking oil, and could not get any more due to rationing.
She used to make home made mayo. Being a resourceful sort, she substituted mineral oil in a batch, and used it on sandwiches for my great Uncle to take to work. He liked the sandwiches, but wondered what hit him about 2 P.M. She could tell him for about three months ( from embarrassment.Dukes on corn bread is really good. NO sugar in the cornbread, that's heresy.
If you ever get to visit a mayo factory DON"T! I have exceptionally disgusting. I didn't eat it for a week or two. I was 7 or 8 at the time so I forgot things quickly. I grew up eating blue plate because that is what mom bought. Now there is only one. KRAFT!!