Should be opened once a month

Depending on the machine model, the shape and location of this filter will be in different places. For most front-loading washing machines, the lint filter is located on the outside of the washing machine, making it easy to see. For top-loading washing machines, the lint filter is usually located right inside the washing drum.
Washing machine drums usually have a removable bottom, and you will see a small plastic cover. Pry this plastic cover up. Then you will see a screw in the middle. Now, use a screwdriver to remove the screw and lift the bottom up. Lift the bottom out, pour out the dirt and scrub it clean. For the inner washing drum, use a cloth to wipe it clean. Then you can reassemble it as before.