For years, we technicians have used a variety of methods to thaw out a frozen evaporator coil in order to restore cooling and replace components. The most common methods are with a hair dryer or a professional heat gun. While these are time-proven methods, I have discovered a new way to thaw these coils without making any mess, and this method cuts down the thaw time in half:
I use a hand-held steam generator, found at Target and Wal-mart stores for under $40. This thing uses 1 pint of water and is ready in 2 minutes. It power-steams the ice instantly off of the coils in a cloud of vapor, and there is no water runoff produced. The ice is evaporated! Takes about 2-3 minutes to remove the ice from the most severely clogged coils. I highly recommend this as a time-saver on your service calls.