Heres a step-by-step guide to follow in order to make sure your AC is clear of potentially dangerous mold accumulation. You will need to be patient during this process; if thats not one of your strong suits, you should probably call in a service technician.
Step 1: Remove the filter from the front grill. If it is disposable, replace it. If it is made in a plastic frame, however, it can be cleaned and reused. Lay it flat in your sink and sprinkle the surface with laundry detergent. Then, cover it with an inch of hot water; just enough so it is submerged. Soak it for 15 minutes, rinse it with warm water, then hang it to dry while you proceed with Step 2.
Step 2: Take off the front grill. In most models, you can remove it by pulling gently forward while at the same time pushing down gently. If you are meeting resistance, there could be some hidden screws at the top edge or behind the control knob door. Put the grill aside once you remove it.
Step 3: Remove the metal cover to expose its inner workings. Once all the screws are loosened, lift the cover straight up. Be careful that you do not let it hit the other parts of the unit, because its edges can be very sharp. Have an old can handy so you can keep track of all the screws, because you will probably be dealing with several different types and sizes. Keep them separated or you could be easily confused when it comes time to reassemble the unit.
Step 4: Check the fan motor for any oil plugs. If it has them, they will typically be made of rubber. Be very careful when removing the plugs, however, because they might be brittle. If they break, they can cause a blockage. If this does happen, you may be able to remove it by using the tip of a small screwdriver. Once you expose the holes, put in a few drops of electric motor oil to each end of the motors body. Do not add too much oil, though use only about three or four drops on each end. And add it slowly, because you could over-lubricate it if you try to do it too quickly.