Dan,
I have an Armstrong Baybreeze Air Conditioner on my 1964 Tradewind and this is from the manual about cleaning coils. " Keep evaporator coils clean. These are the inside unit cooling coils. The coil may be inspected by removing the air filter and looking at the inside of the coil with a flashlight. For a complete inspection it may be necessary to remove the evaporator fan. If the passageways between the fins are plugged , carefully brush down the inner surface with a fiber brush or cloth to remove surface lint, taking care not to flatten or damage the fins. If clogged in depth it may be necessary to have the coils steam-cleaned. Hope this helps.