I had a Logitech mouse years ago with rubber grips that started breaking down to that slimy surface. Whatever the material is. I haven't seen that for years though.

Mouse wheels used to do that all the time with me.
Hasn't happened in years tho, ever since I switched to a trackball.
Cause there is no scroll wheel for it to happen to 🤣 .

It's a huge problem with foams as well. Such as the insulating foam in Personal System/2s, or Polymoogs (which it gets really nasty as they layered it behind the front panel). You end up needing crazy industrial solutions to remove the residue...

The foam and rubber that experiences the 'melt to slime' phenomenon definitely is derived from the same source and is made in the same way. I am not sure what the exact process is though. Not all foam & rubber experiences this, so I myself am curious what the exact compound is.

It's not UV damage, at least not for some rubber components. Must be a slow chemical reaction.

This is also a reason for some very old HDDs failing.
I've had a Micropolis 1325 not working anymore because the write/read heads wouldn't move out of their parking position. The cause? The rubber, that was used to cushion the heads turned to black goop over the last 30 years.
Here's a video, notice how the heads aren't moving at all. The HDD turned itself off after a while. https://www.youtube.com/watch?v=L5yzmnRVj4U&l … sYZYcTJw-STeaUg
Took me several days of careful cleaning, but it works again. Don't know for how long though 😉

Where I really hate it is old laptops. I've got several Thinkpads which have their rubber coating turn into a somewhat sticky and ugly mess. Doesn't happen with all models though. My 600s are affected, but the slightly newer T23 isn't.

Yeah I saw this happen with a Packard Bell 2400 baud modem, the rubber feet were looking kinda melted and slid around on the bottom. Unfortunately I tossed that thing, oh well can't keep everything. 🤣

I've had that happened too with an old Logitech MX500, an ASUS gaming laptop, Wacom pen, an old DSLR, and some other rubber-covered stuff. Long ago I searched for a solution and people from car forums suggested a Meguiar's product. I think they suggested "'natural shine" for rubber/vinyl, but what I got was the "supreme shine". It helps with scrubbing and cleaning but will make the surface smoother & glossier (besides leaving your devices smell like cookies for a while).

Heat and accumulation of dust/dirt will probably quicken the 'sliming' process with these materials. It's def not pretty.

It also happens with the rollers on some printers. Suffice to say, if paper gets gummed up with that stuff, it makes for an interesting experience to dismantle and clean up.

Very common with IBM PS/2 Model 60s & 80s: the inside of those boxes is usually full of slime. 🙁