With great respect to responders, I disagree about the 'no liquid or spray'. I risk being excommunicated for this

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I posted recently about cleaning under the D key on an Apple keyboard where spillage had occurred, after flipping its key cover off. Actually very easy to do, with no resultant damage.
I first used the sharp end of a nail file veeeeery gently (are you shuddering yet?), then an interdental brush, and finally compressed air, before spraying with CO contact cleaner, and putting the k/b out in direct sun. The D key is now working again.
Alas, I have had to do repeat treatment, but on the (left) Command key this time. It's a little more tricky getting it back into position, I have to warn, and a further repeat may be needed.
Piggybacking this thread, what best to clean the keys on an Apple bluetooth keyboard? The numeral keys in particular have become rather grubby. Spectacle lens cleaner, or just a damp microfibre cloth?
Hugh