I use my extra refrig to cold stabilize my wine after fermentation is complete. It helps to prevent tartaric crystals (although not harmful) from developing and it helps clear the wine.
Depending on how much you are cold stabilizing, make sure your shelf is fully supported. I remove my shelves, add a piece of plywood, and turn the setting all the way down. After 2 - 3 weeks the wine should be cleared and ready for a final racking before bottling.
I'm wonderng what the law reads in regards to smoking in an old fridge. I have 2 stand up freezers I use for tool storage. I never did thinking about sitting inside of it with a nice glass of wine, and a wine making implement with smoke coming out of it. Kinda puts a spin on the wine making huh?