A man I worked with rolled $100 dollar bills and hid them from his wife in the barrel of a 12ga shotgun. He called it his “she” money. That worked good until he grabbed the wrong gun to go bird hunting one day and blew $100 bills to smithereens.
Collectibles and precious metals. Bought from small vendors, that take cash. I read somewhere.
A few years ago, Grandma picked a very old/beat up book out of a Junk Book bin for me.
First good thing was the book was an early edition Kipling I'd been looking for.
The bonus was the dozen or so $100's had been left as "bookmarks" by a previous owner.
Really pleasant evening reading sessions when you come across things like that.....