Just throw it away, then you'll discover what it is and really need it, but it will be gone.
I did that once with a weird shaped piece of plastic I found in my work truck. Not a week later, I found it was one of the foot inserts for the leg bottoms of an expensive aluminum folding work table. Now with only three of the four feet, I cannot level the table without shims.
Put it in a box labeled Misc., and save it.
Saved my self a bundle recently. I had a weird clamp on my stern rail, and some "unknown" parts in a tub in the cabin on my new boat. Almost removed the clamp and tossed the parts. Last weekend, I was cleaning out under one of the berths, and found a bag containing the rest of the parts to a really nice stern rail mounted outboard motor hoist. Good thing I didn't toss the other parts.