Well. let's see. Sometime before 2013 when I actually won bids on Shopgoodwill, I won 4 INTV consoles. When they arrived I immediately began the cleaning up process I perform on every computer/game console that passes through my door. Same goes for used TVs, VCRs, Stereo equipment, you name it.
One of the four INTV systems rattled really bad. Upon opening it I found that the heatsink had come loose from the processor. So...I put it back where it was suppose to go. In the N64 I got most recently out of a dumpster it was full of roaches...some still alive. They aren't alive now and none of them escaped (Bug Hunt anyone?). And one 810 disk drive I bought arrived making small rattling noises...yet it worked like a champ. Upon opening it up I found an entire family of Japanese beetles (lady bugs) with a few dead. That last one I wasn't upset about...I actually laughed about it as it was not something I would have expected and I'd rather find those than roaches any day. But those things sound like small rocks when being slammed around inside an electronic device.
Around 2005 or 2006 I won an RCA SGT-100 and SGT-200 CED videodisc players. One of them rattled (becoming a regular thing) and, again, opening the top cover revealed a large, flat metal file. How it managed to keep from damaging anything inside is beyond me. The SGT-200 had a hornet's nest in it and when trying to play Stripes on one of the players it would get to a certain spot and just hang. Although notorious for errors I took the disc out to see if there was anything I could see wrong. Well, some how there was mud on the disc itself. I know there was really no known way to clean these discs but I took a chance and washed them just how I would a vinyl record...mild detergent and warm water. Once removed the disc played like new...no bad spots at all.
The last thing I think I have is with a Magnavox Blu-Ray Player my wife and I bought from Wal-Mart. This was the large model when Blu-Ray was pretty much the new medium. Up on getting it home, setting it up, and turning it on, there was a disc in the system. It was a Disney animated film, too, but I don't remember if it was The Princess and the Frog or Pocahontas.
Other than that it's the usual dust, dirt, webs, dead insects.