Relative delivered a custom-built desktop PC that they no longer want. Inside it is the dustiest computer I have seen in decades, with brown dust caked and clogging the vents. I am amazed that all the fans still work. I drained the battery on my handheld blower, and I still have a ways to go. I suspect this was assembled about fifteen years ago (processor is an i3-2100), put into use, and then the case was never opened again.
Boots perfectly. Fans are whisper quiet. Mechanical hard drive spun up fine and passed all checks. It may be a little old, but my relative did a nice job putting this all together.
I'm going to see about swapping in an SSD, then checking how usable it is (current operating system, videos etc.). If it's good, I'll try and pass it to someone in the neighborhood.

@GamesMissed

I pass around older iOS devices in a similar manner. If usable, spread it around!

@davidhmccoy Yes! If it can still get security updates and patches, if it still browses the web ok (loads all sites, plays videos fine), if it doesn't lag, then it's still a usable computer. Enough people around here are on cell phones as their only computers. They can have better.