Earlier this week my bike had some work done, some of that nitty gritty work that only gets done once in a blue moon, and we found something.
Hint: It used to look like this. Scale is only slightly bigger than a pencil eraser.
Two years ago one of these button magnets was bonded to my bike's bottom bracket to act as the pick-up for my SRM. Two years of sweat, nutrition drink, road grime, and cleaning solvent left only an oxidized miniature hockey puck. It disintegrates further each time I touch it. I have no idea how I was still getting a strong signal from my SRM.
But more importantly: gross.