Hey @adams.barbara, that cider vinegar marinade your uncle uses reminds me of when I tried something similar. I marinated pork chops in apple cider vinegar with some garlic and brown sugar for about 18 hours. They came out so tender, almost fell apart when I grilled them lol. The acid in the vinegar really breaks down the meat, but adding a bit of sugar balances the tang.

Levi's from the 70s have a specific back pocket stitch.