How to remove brown/sweat marks from wires?

I woke up this morning with these brown marks randomly on the wires, i’m not sure if it’s sweat damage since i fell asleep with them on and it was extremely hot in the night or if it’s something else - they are a little bit pokey too with a tiny bit of the material poking out like it’s been burnt (sorry for the bad quality picture)

[Re-Titled By Moderator]