The air filter prevents dirt from getting into your chainsaw. A dirty or damaged air filter can shorten the service life of the chainsaw.
In general, an air filter should be thoroughly cleaned after each use. In more demanding conditions, the air filter should be checked and cleaned every time the tank is filled with fuel. If the filter has a hole or is cracked, it should be replaced immediately. Very fine dust can collect in the air filter. The dust can clog the air filter and cannot be removed by brushing it away or knocking it out. The air filter must be cleaned under running water with a cleaning agent.
Pro tip: STIHL recommends cleaning the air filter with STIHL VarioClean Eco
Pro tip: For effective cleaning, STIHL offers the Care & Clean Kit MS Plus
Pro tip: You can also clean the air filter in a washing machine with your protective clothing.