Can a trim-pot wiper or contact point gets oxidized over time? For example when a potential (high) current is flowing and the contact point of the wiper on the resistive element heats up a little. I don't mean hot, just a little warm because of resistance. The effect takes years before it will be noticable.
For example this trim-pot, it is connected to a laser (CD-player).
After years of working properly, most of the time when the wiper is moved, just a fraction, the laser will work again. Maybe it works again because more current is flowing and boost the laser diode (above limits), however could it be possible that previous position was oxidized (by heat and vaporization of something - maybe resistive element, carbon, vaporised by heat), the resistance increased (a thin film is formed on contact point) and because of this the laser is reduced in power. So the laser is not in bad shape, the pot is in bad shape and caused the problem.
A couple of months ago I have taken apart some equipment and on the lid I discovered some black dust/dirt (?) positioned above elements that heating up when operating. I don't know where the black dust came from or what it is however it is caused by components that produces heat.
So I wonder if this is possible inside a trim-pot when it produces some heat, does the contamination (vaporization of something) cause malfunction/changes the value of the pot. Is this possible?
This is all curiosity, it is nice to know.