How to remove the buttons of IBM USB Keyboard W/ UltraNav

[msafi]

I have had my old trusty IBM USB Keyboard with UltraNav for a couple of years now and can't imagine using any other keyboard. However, it is starting to get worn out but I think the problems are fixable.

One problem was with the buttons of the pointing-stick being difficult to press. I removed the button and cleaned underneath it, and now it's better.

Other buttons on the keyboard, such as the Enter and letter buttons are being stiff as well. I want to remove the buttons and clean underneath them, like I did with the pointing-stick buttons. How can I remove the buttons?

Thanks,