If frozen moist is the problem for the shutter to stick, you may solve it by using acetone instead of alcohol or electronic spray.
the last two options do not evaporate totally, so some stuff stays behind and the problem is not solved
Acetone dissolves water and evaporates totally together with the water.
I always use this to dry my laboratory glass. It's an old procedure to dry without any remains.
Just my 2 cents,