Ok now you have entered my dept
..I dont clean mine .. I use quality filters
it appears from the picture you have a pleated filter on the right side ?? if so thats good..... ...
But I clean everyone elses that dont ...
1st ...TURN OFF THE MAIN HIGH VOLTAGE POWER TO THE INDOOR UNIT..
.... safety 1st
2nd you should inspect the coil to see if it is even nessesary
hint : make sure you are inspecting the coil side that the air flow is entering...... If you have used a good quality filter over the years it should not be nessesary to clean the coil....
if it is dirty: you can either go to a AC supply house and get a coil cleaner that sprays on it to help break up the dirt or if its not impacted badly you can use a mans small hair comb to lightly remove the build up being careful not to bend or damage the fins..
... Hint the ID and OD units are on seperate breakers
notice: TURN OFF THE MAIN HIGH VOLTAGE POWER TO THE OUTDOOR UNIT ALSO.....
!!! Your outdoor coil needs to be washed well with a garden hose.. every year!! again make sure the pressure is not to high as to bend or damage the coil..
If the indoor coil is dirty after you clean it .. use a good quality Pleated Filter installed properly and this will never be nessesary again...
If you have any questions just let me know I'll be glad to talk you thru over the phone this evening.. ..