Is it possible to clean the front switch?

Greg wrote:
I have a Philips PM3323 digital oscilloscope which has not been used for
some time. It has developed a problem where both A and B channels have
become very noisy such that the noise on the display is now larger than the
wanted signal - making the scope unusable. Timebase and y-axis functions all
appear to be still working OK.
Can anybody tell me whether this fault is likely to be economically
repairable?

Many Thanks,
Greg