An air conditioner uses a series of metal coils to dissipate the heat generated by the compressor. The coils can become dirty over time, due to exposure through a grille to outside contaminants sucked into the air conditioner. You can make your own cleaning solution to use on the coils -- cleaning them so that they operate more efficiently than they would otherwise. Your homemade air conditioner cleaner requires supplies from a supermarket and an AC cleaning tool from a hardware shop or a pool and spa supply shop. The AC brush is specifically designed to use on coils without causing any damage.
Turn the air conditioner's thermostat all the way clockwise. Unplug the unit if it is a portable model; otherwise, trip the circuit breaker at the fuse box to discontinue power to the air conditioner.
Pour 443 ml (15 oz) of washing up liquid into a measuring cup. Pour the contents of the cup into a plastic container. Pour 425 g (15 oz) of bicarbonate of soda into the measuring cup. Add the soda in the measuring cup to the plastic container. Stir the mixture in the container with your finger until it has a pasty consistency. Wash your finger off afterward.
Remove the screws surrounding the grille vent plate that is on the back of the air conditioner with a Phillips screwdriver. Remove the plate and place it aside. Wipe off the coils that are now exposed with the AC cleaning brush to remove loose dirt and other contaminants.
Dip the brush in the mixture inside the container. Lightly scrub the coils with the brush, refreshing the mixture on the brush every half coil length. Continue to do this until you have applied the mixture to all of the coils.
Wash the brush off with tap water in a sink. Lightly scrub the coils with the brush again.
Replace the plate on the back of the air conditioner and reattach the screws. Plug the air conditioner's power cord back in or, if the air conditioner is not a portable model, restore the electric power at the fuse box. Pour any remaining mixture into the kitchen sink and wash the bowl out with washing up liquid and tap water.
Take the opportunity to clean the grille when it has been taken off the back of the air conditioner.
The cleaner that you make is not poisonous, so it is safe to use with children and pets nearby -- providing you don't allow them to eat any of it.