You mentioned cotton. I well recall how (I believe it was 1980), on Veteran's Day .. the stock market was closed. However, a very few of the commodity markets were open, limited hours.
Cotton was incredible that day. It opened limit bid. Traded limit offer ... Then, the icing on the cake .... It closed SHARPLY unchanged.
The good ol' days, where a local could pay for his seat in a day's trading.
Public beware.