How to remove the exhaust round screw of rainbow electric heating treasure?

Remove the exhaust round head screw of Rainbow Electric Heating Bao with a screwdriver. The merchant will put a label on the connection position of the screw and nut, find the position of the trademark and directly find the position of the nut, and separate the screw and nut with a screwdriver. After removing the screws and nuts, lift the semicircle above, and you can see that the iron box is full of refractory materials.