How do you remove black coating from tawa?

Could you please elaborate on the steps needed to effectively remove the black coating from a tawa? Are there any specific cleaning agents or tools that are recommended for this task? Additionally, are there any precautions that one should take to ensure the safety of both the tawa and the user during the cleaning process? Lastly, is there a difference in the removal process based on the material the tawa is made from, such as steel or aluminum?