Step 5: Remove surface dirt and dust from the front fins. Be extremely gentle, however; use an up and down motion. Do not go side-to-side, or else you may bend the fins. They are made of extremely soft aluminum and are easily damaged. When you remove the surface dirt, spray the fins with a de-greaser, which you should be able to find at any hardware store. If you have some Fantastic spray cleaner, that would work fine as well. Let the de-greaser stand for about 15 minutes in order for it to loosen any hidden dirt. Slowly pour warm water on the fins to remove the dirt and cleaner make very sure that you do not let that water touch any electrical connections or other parts near the coil. You may want to cover the motor with a cloth rag to make sure it is protected from water. Never use any kind of high-pressure water or air, because this can cause dirt to be driven further into the fins.
Step 6: If you have any bent fins, straighten them with a fin comb or something soft, such a Popsicle stick. This will increase the airflow through the coils and help your AC units efficiency.
Step 7: Repeat the above two steps for the condenser coil, or rear fins. You will probably need to remove a plastic cowling. Use the same kind of caution, however, because that coil is filled with high-pressure refrigerant.
Step 8: Wipe away any dirt buildup from both fan blades with a soft rag. Again, take care not to bend the blades, because that will cause a vibration that could damage the motor.
Step 9: Vacuum all surfaces, including the grill assembly front and back. Vacuum the underside of the metal AC cover as well, and use a damp rag if necessary as well.
Step 10: Drain any water that may remain in the base and let dry for a few hours. After it has dried, turn on the power and see if everything works properly. If so, turn the power off again and reassemble.
Repeating this procedure yearly can both extend the life of the unit as well as helping to keep your home free of potentially dangerous mold.