Refrigerating Circuit Board Based Attenuator

Hello:

We just purchased a dual mono set of circuit board w/ resistor based attenuators for our monoblocks. They are stored until the technician who works on our amps. is available to install them.

Given the heat and humidity in our area: would someone please guide me on the benefits or detriments of storing these instruments in a refrigerator or perhaps the freezer. Would storing them in the freezer -- as opposed to the relatively milder temps. of the fridge -- potentially crack the plastic circuit board or threaten resistor integrity?

Thank you for your technical expertise and happy listening!