Vinegar, with a surprise ending

I remember long, long ago often seeing my grandmother drink vinegar. When a salad was eaten, she used to pour the small amount of plain vinegar dressing left in the bowl into a glass, and drink it. Nothing would be wasted. I think my sister Tricia drinks vinegar in this way too. I must ask her. If you read this Tricia, send me an email please.I've been reading about vinegar this week and