@vy it's most likely *some* kind of misuse... but which...
@vy ahh hmm
"If you leave it on too long or run it too hot it will burn off the solder and go black again"
https://www.instructables.com/community/Soldering-Iron-tip-is-turning-black-and-will-not-t/
@vy and seems in part to being very cheaply made tips
@f0x ah, cheaply made, yes. that’s the one I had
@vy @f0x you can recondition bad tips with some success by pouring some flux on brass or steel wool, or even a wire brush, the scrubbing the hot tip with it. Be generous with the flux! Once that's been done, melt some solder onto the tip and scrub it in with your scrubbing implement.
it'll take some patience and a fair amount of solder, but it does work!
@vy @f0x this is the same technique used to "tin" big iron castings that hold bearings in some antique machines.
the bearing material is a tin/lead alloy colloquially known as Babbitt that is cast into the desired bearing shape in the iron castings that hold them.
the castings are tinned before pouring lead/tin alloy in them to help it stick.
@f0x I didn’t even know tips could wear out! That just sounds like bad design to me,