I have a Maytag refrigerator, about 6 years old. I need to store it and won't be using it for about 6 months. Should I plug it in, or is it OK to leave it not operating. Also, it is in a garage that gets very cold, like below 32 degrees when the weather is cold outside. Is this OK?

I don't think there is any problem leaving it unplugged, it must have sat in a warehouse for several months before you bought it and it worked when you bought it, shouldn't be a problem... check the link below dealing with storing a fridge in a cold environment

Storing a refrigerator in a cold environment

The issues I know of concerning moving and storage is avoiding placing it on its side to avoid issues with oil getting into the gas dryer and having to blow out and replace refrigerant, and then also running it from time to time if in storage to keep the compression motor loose.

I have an extra fridge that someone else stored with the door shut. Id probably store it with the door slightly open next time. Smelled "plasticy"... but once it was fired up it was fine. I don't know. I suppose closed is better for keeping it clean.

Okay to store unplugged but may have to have freon checked when you want to use it again. That is what people do when they are storing an appliance, unplug it.

Clean it out really well and leave the door ajar. My parents put one into storage unit with door closed for several months while their house was being built (many delays) and when it came out of storage it had a funky smell. They ended up buying a new fridge.

I was told by my mother to store my fridge slightly open and put a piece of charcoal on each shelf to help dry out moisture to keeep it from getting moldy, and running it once it a while to keep it "alive"