Unplug the air conditioner. Then remove the air unit's plastic trim panel, most likely by snapping it off. Have a family member or friend help you slide the air conditioner out of the window and set it onto a worktable.
Remove the unit's mounting frame and case by using a screwdriver to undo the screws that hold them into place; the screws are typically located along the bottom edge of the case. Set the screws in a safe location so you don't lose them.
Straighten any bent cooling fins using a specialized fin comb. Use a vacuum with a soft brush attachment to remove any dust and debris from both of the unit's coils.
Spray the two coils liberally with a can of foaming air conditioner coil cleaner. Allow the cleaner to sit on the coils as recommended by the manufacturer.
Wipe down the air conditioner's fan blades using a general household spray cleaner and a soft cloth. Open any of the fan motor's plastic- or rubber-capped oiling ports and lubricate them with a drop or two of electric motor oil for lubrication.
Vacuum the unit's filter or replace it with a new one, especially if you see any mold spores on it or smell mildew in the air. Pour a cup of bleach into the access opening of the condensation drain line to kill any mold and mildew that's growing in it. Put on a pair of protective latex or plastic gloves and wipe the water drip pan using a cloth dipped into bleach. Allow all of the parts to thoroughly dry before reassembling the air conditioner unit and placing it back into the window.
