Not based on my consumer (non-expert) experience... It seems to turn to a blue green jelly in carbs and then eventually a lacquer.
Either would be acceptable, but access would be easier and less hazardous if the system was kept in a controlled environment of say around -30-40°C.
Don't talk to me about freezers..........had two new ones pack up in two years............now looking to see what is available in the way fo better ones................bastard things.
You've been unlucky or they are overheating. Even the cheap ones are reliable.. Just !keep the airflows good and the filter panel clean.