After a long summer stay I noticed quite a bit of ice build up on the cooling fins inside the RV fridge. A quick way I used to melt it was to use a hair dryer. Moved the food down to the bottom shelves and blew the air on the iced fins. Took only around 10 minutes to completely melt off.
Works well for a quick freezer defrost as well. Saves so much time that you generally don’t need to move your food to an ice chest.