That is abit where I am at with mine. There are in alot of some YouTube videos some that are either replacing the entire relay switch. To get at it properly to clean, some desolder the switch. The contacts in the relay is what they are cleaning.
The top cover of the switch if can be removed easily enough, without damaging for access to the contacts. Problem is, there are resistors, etc., In close quarters around the switch, which can be damaged if attempting with out caution.
So, yes, if can sell a small hole in top of switch, without plastic debris falling into the switch, further complicating contact operation in relay, would look closely and possibly be able to directly insert small plastic straw onto the contact portion. Cycle switch while light spray several times.
And after all this to consider, whatever method used to clean, no guarantee it will fix or help problem.
Measuring the voltage level operating the switch may well come into it. It gets more involved as well.
Maybe bubo will say.