HP-67 bouncing keys

[Kees Bouw]

UPDATE

After Tony's reply (thank you Tony!) but before Geoff's and Randy's reply, I cleaned the keys again. I already suspected that DeOxit gold (G100L) was not so good for cleaning and I used DeOxit red (D100L) first. After that I used 97% alcohol and after that DeOxit gold. All done with paper strips. It worked very well, no more bouncing keys. However, it turned out that soaking the paper strips (holding them in the bottle) resulted in far too much liquid because the plastic film and some of the case and keys also had (presumably) DeOxit gold on them. I did clean the keyboard to remove excess liquid of course but apparently still a lot remained under the domes. So now I am going to clean everything again. Next time I will use Geoff's method. @Geoff: How exactly do you rinse with IPA, do you pour it over or immerse the whole keyboard? I am also going to look at investing in an ultrasonic cleaner as suggested by Randy. Thank you all for your help!