First is first....maybe because it was one of the easier things I could do. Some of the bass keys and some of the treble had tape residue on them from being labeled A-G# for students. Most of this had already been removed but there were still a few that remained.
I first tried some heavy duty Goo Chewer, but it did more damage than good. It whitened and put dips in the keys. I then tried WD-40, much to no avail. I almost forgot I also tried Nutella thinking it might help with the oils, no luck.
The final solution came by way of a XACTO knife with a squared edge blade. It took a little time but the results were great. I think I will eventually put new keytops on each of the keys but this was a fund project for the first day.
Next project...cleaning some surface rust off of the pins and coils....