Sure, everyone lamented long and hard over the demise of Polaroid and Kodachrome- but not one single tear was shed Mr. Spotone's way. Yet how many fiber based B&W prints would've hung on gallery walls without him? And there above lies one of the last remaining bottles of Spotone in photographic history- and it's mine! The liquid that has since come out to replace it (different manufacturer) supposedly sucks, but I'm hardly in a celebratory mood since I no longer have a darkroom.
For you digital young bloods- any B&W printer worth his salt could be seen with a #00 or #000 brush (yes, we were all pointillists back in the day) in one hand, and print in the other along with a bottle of #3 (the anally inclined could also mix it with #1 or #2 to make it warmer or cooler to match the color temp of the specific papers, particularly for a large spotting/retouch job). You'd place brush in liquid, work off the excess, then dab your tongue with it to get the appropriate density that matched the area you were going to spot.
I mention the latter because it was none other than Alex Harsley, who himself had suffered significant ill effects from prolonged darkroom exposure, that brought to my attention that one of Spotones's key ingredients was none other than a particular form of cyanide! I gave him a look upon hearing that one- he returned one better.