Opening up a remote can be tricky in my experience, but my old A3 has been giving problems so I had to make a plan.
Instead, I used small amounts of Q20 sprayed into the key etc. gaps and then thoroughly exercised the affected keys and selection wheel.
The keys are about 50 to 75% improved, good enough for me.
The wheel - first it froze up and was near impossible to turn
but after quite some time and more exercise it's now as good as new
I know... not the ideal solution, but perhaps a harmless enough alternative...
A "switch cleaner" spray may well do better.