I found this keyboard today in my drawer, and decided to try and revive it. The project got, um, paused indefinitely over a year ago, when I stupidly got superglue inside the key switches, and pretty much ruined them.
Today I decided to take a little bit of risk -- since the switches are broken anyways the way they are -- and applied a little bit of acetone to one of the keys. Lo and behold, it budged! A little bit of wiggling and scraping and removing the gunk from it, and it works almost as well as it used to. Great! Only 21 more to go!
Three hours later I pretty much have all the switches working (I had to replace one of them, but fortunately I still had some spares), and I am back to where the project was last time -- I have the rows of the keys soldered, and now I need to solder a diode to each key and then connect the columns, and connect everything to a Pro Micro.