I would advise using a Contact Cleaner as suggested by XZ4 above, (WD40 make one) rather than WD40 itself on a switch mechanism. WD40 is oily and will attract dust/dirt over time faster which causes the problem.
I did mine 1 year or 2 ago been fine ever since.
Don't know which model you have, but Note the early Evoque's can suffer with button issues due to a timing issue on start-up, this usually happens more when cold. Cant fix that, and usually a powerdown fixes it.