Stone rust remover can clean the yellowed rust spots on the fired board. The specific operation method is as follows:

1. First, rinse the rust on the surface of the fired board. Attach two paper towels as shown in the picture.

2. Then pour the stone rust remover on the paper towel to soak the rust on the surface of the fire plate.

3. Next, leave the fire plate for five minutes. At this time, the stone rust remover will react with the rust on the fire plate.

4. After five minutes, you will find that the paper towels laid on the burning board have turned purple, which shows that the stone rust remover has a reducing effect.

5. Next, remove the paper towels laid on the burning board and rinse them with clean water.

6. Finally, through comparison, you can see that the rust on the surface of the fired plate has been removed very cleanly, as shown in the picture below.