These are all techniques that will work, but since you are in a place where water will freeze almost immediately and all the work will take many hours, why don't you see if somebody will just dunk it in a tank and clean it for you. Compare the cost of doing it to what you will pay yourself at minimum wage and the cost of materials to get it done and the pain of getting rid of the waste water. I just went through this before it got really cold and wish I had taken it in. I used a 5 gallon bucket with some biodegradable cleaner to soak clean the smaller stuff.
Being wet in below zero temps is not a good idea. Trust me on that.
