agilent DSO-X 2002a, knobs not working properly

[wiss]

Hi
I have a few DSO-X 2002a at work.
A few of them is starting to develop problems with the some knobs, the trig in one case and the cursor in another.
I removed the cursor-switch-thingie and opened it up (picture). I expected some dust in there but no, seems clean.
Now I want to clean it but there is some grease visible on the contacts, what kind of grease is this? Where could one get more? (within EU preferably).
or:
Does anyone know the where I could get replacement switch-thingies?