If you remove the meter movement from the panel and then remove the cover from the meter, you can use a can of dry air to blow any possible contamination from the movement. However, hold the meter pointer against the meter face so that the air doesn't slam it around and begin blowing with the can far away from the movement. You don't want to start with the can right at the movement and then screw the helical springs all up and ruin the meter. As mentioned, because the movement is pretty well enclosed, there really shouldn't be any foreign material in there. But you never know.
I would never consider using any liquid to clean a meter movement.
If you start loosening the adjusting screws, you have to be very, very careful, for you can crack jewels in the movement bearing and ruin the meter when you retighten the screws.
Static build-up can be reduced by wiping down the meter face with a cloth dampened with a water and Downy fabric softener mixture. To see if static is the problem with a stubborn meter, simply open your mouth widely about one inch from the meter face and go "Hahhhhhhhhhh" on it to fog it over or introduce static-killing humidity to the meter face. The indicator needle should hop right to zero if that's where it's supposed to go.
Dean