950i knitting machine?

Set it with the buttons at the top and spray or drip some penetrating oil (I like Kroil, but there are other good brands) into the area where the buttons are. Let is sit awhile (few hours) and test the buttons. Repeat a few times, they will usually free up. Do not force them if they are not ready.
Next alternative is to remove the handle and plastic top so you can get penetrating directly into the button mechanism.
But the Kroil has always worked out for me.

John Sullivan
January 2016

Some people recommend using a hair drier to soften old grease on knitting carriages, then working the buttons to free them.
Check that everything is clean before applying new oil or grease to your machine.

Sue
November 2014