So I've had my fair share over the years of converting everything and anything into temp and humidity controlled containers. I usually start by unloading my truck in my drive way and soaping the entire thing up and hosing it off, I do this a couple of times. If it's for normal use I won't sterilize, dish soap is good enough. I used Lysol on my small frig I got a few months ago, I had a brain freeze and wasn't thinking, well it's extremely hard to get rid of that smell.
Here's my advice for anyone looking to clean and sanitize a freezer or frig. First use dish soap on the outside and inside, outside preferable and hose off to get every nook and cranny clean. Make sure to use a soft sponge in the grooves of the gasket on the door. The gasket is a harbor for bacteria and mold. Next, once the inside is dry, KEEP it unplugged and close the door overnight. Clear out your nostrils with fresh air and then open the door and smell. If it's good move on to the sterilization phase below. A little for-word all freezer and fridges when they are not turn on and at room temp (well at least not cold) they will all have a slight funky smell, it's just the nature of the materials used. If you still smell a slight smell that might be normal to a frig plug it in and smell again the next day. If it's gone then move on to the sterilization phase.
If you still smell something I've learned recently, since my new cave that turned out to be a bust had a horrible freezer burn smell even though I scrubbed it with soap 3 times, bleach does more than just sanitize, it kills everything including odors that regular sanitizers don't touch. So my new regiment is to, make sure it's unplugged, wash it with soap and water, then take a spray bottle with a diluted bleach solution and spray it on. Wait no more than one hour and hose off, then scrub with dish soap again. After that continue until the bleach smell is gone. Once dry do what I suggested above close the door with the frig off and smell.
If after this it smells good then take a bottle of mixed up Star San and spray the entire interior and door. Let it dry and you're good to go.
Basically what I learned is if you spray simple green or lysol or something else with the intent to get rid of a smell and you're stuck with that chemical smell, then Bleach is the intermediate step where it will kill other smells artificial or natural, but it is not hard to wash off, so you need stages.
