How to take out the toilet water inlet faucet knob
Finally, I fixed it. I used a big flat screw driver to pry the knob off. One step for a quarter turn. The knob is loosened in about two full turns. Then, use a spanner to remove the nickel painted copper cap that holds the faucet filter cartridge. Once removed the cartridge with a pliers, the dirt and mud is draining out. The cartridge is full of mud. I cleaned up before putting it back to the shelf to remove the faucet.