I cannot throw away the little spray tubes that come with aerosol cans of chain lube or penetrating oil. I went through a period a couple years ago when I lost every spray tube that came with the cans, and got tired of not being able to apply the liquids precisely. So I vowed to always save the spray tube from every can before I throw it away. That’s why I have a pile of red plastic spray tubes in one of my toolbox drawers.
Other people save odd little things. I know a guy that for years, every time he emptied a “rattle” can of spray paint, he completely sprayed-out the aerosol then cut the can open and rescued the steel ball inside. As a kid he was curious about what was rattling around inside the cans, so he cut one open and thought the steel ball was kind of cool. He probably has a hundred or more of the balls in a jar in his shop, the last time I checked.
My dad, a farmer, had a “thing” for seed corn caps, the trucker-style baseball caps given away by seed corn companies as free advertising. At one time my mother took it upon herself to “thin the herd.” Luckily, Dad intercepted the garbage bag full of caps before she was able to sneak them out of the house. A spirited discussion ensued ...
I think each of us has some small “thing” that we obsessively collect. Some are for display and conversation-starters. Others are kept just because … well, “just because.”
There’s no other explanation.