It wasn't really the solder itself that was a problem; it was the process of making it. We used to find old rolls of the stuff hidden in various racks at the station all the time. My only gripe was that it was mostly too big for modern circuit work. ...sigh...those were the days: 16 awg bus lines terminating to barrier boards: easy to test, diagnose and fix... but I digress.
The saddest day of my career was cleaning out the old satellite reciever building and throwing away literally tons of old equipment. The copper in the PT's alone was worth a fortune, but none of us had the time to break it down or the ability to haul it all off, though I did nab a few choice components from the old Beta automation system, an Odetics 9000, which was made by a space probe company who did automation robotics on the side and all of the old ADM audio board's spare parts. All I need is a frame and power supply and I've got what amounts to a full analog API-style console.