Video : 
You have to learn until you die!
I have a little collection mania. Well, hate to throw anything out. Since I'm interested in electronics, this also applies to old PCB cards. I had a whole box of cards that were too good to throw out.
But I was suddenly in need of the box, for another project :-) So I had to clean up a bit, and sort out what was still worth anything.
Now the box had stood ten years and gained moisture and rust, And,,, well 2/3 was therefore nevertheless thrown out.
The last 1/3 of the PCB card which had good components that I wanted to take the time to solder out. before the rest are thrown away.
My cousin had is pretty amazing way to do it!