help to clean my Chivalz 6L humidifier – white stains from minerals

Hello everyone!
I have a Chivalz 6L Cool Mist humidifier, and due to a cleaning oversight, some white stains have appeared that I can’t seem to remove. From what I understand, these stains are minerals from the tap water. I’ve tried cleaning them with baking soda, kitchen white vinegar, hot water, and dish soap, but the stains are still there, and I don’t know what else to try to get rid of them completely.

If anyone has experienced something similar or has an effective method to eliminate these types of stains, I would greatly appreciate any advice or tips.

Thank you very much in advance for your help!