Before it is too late and the functioning of the fan is hampered, it is essential to clean the fan periodically. It is quite easy, honestly. Check it out here.
Prep work. Wear a mask and gloves before you begin cleaning. Switch off the exhaust fan and disconnect all the plugs and wires that are connected to the fan.
Clean the mesh. Open the mesh and clean it first. Prepare a solution of ½ a cup ammonia and one cup of boiling water. Place the mesh in the mixture and let it sit for an hour. Then scrub gently.
Clean the blade. Prepare a solution of hot water, a few lemon slices, white vinegar and baking soda. Dip a cloth in the solution and clean the dirt, grime and stickiness off the blades.
Final cleanup. Let the blades and mesh air dry. Reassemble the exhaust and it is ready to be used.