I took advantage of my electrical problem yesterday to defrost the fridge and freezer. In the fridge it’s always half of the coils that turn into a mass of ice while in the freezer it’s the back wall that gets thicker and thicker.
The fridge ice falls off the coils very quickly after turning off the power, but the freezer ice behaves as though it was attached with crazy glue. It’s a bad idea to use anything sharp to scrape and a hair dryer or other heat source can also cause damage.
The solution is to lightly coat the freezer walls with a non-salted oil, such as vegetable or olive. Ice will build up as normal, but after letting the fridge sit for about an hour a gentle tap will loosen it. Dispose of the ice, wipe down the walls, and reapply the oil before turning the fridge back on.
I would not try oiling the coils in the fridge.