I have to try it some day on some nice keyboards I have (Dell stuff from 1990 with "hard click"). I have a lamp made of two 27 Watts black fluorescent tubes, done for making PCB's with UV-sensitive photo emulsion. It worked great for that purpose... I also have a Mitsumi PC keyboard from 1995 with exactly the same internal design as A1200 keyboards. Contact elements are identical, not sure for springs - A500 had steel wire springs, this Mitsumi kb has rubber "wine glass" shaped elements. Keys are also identical in shape, but the style of letters is different.
BTW a strong source of UV is an electric arc from welding. I've tried this with succes one day (for PCBs), just found an old, steel car wheel rim and massacred it with welder for 20 minutes. The only problems are electricity consumption and possibility of sparks hitting retrobrightened plastic parts...
