Blackening is a common oxidation phenomenon when the iron head is used for a long time. To solve this problem, there are the following methods
1. When the power is not on, file the black oxidized part with a file, and dip it in Rosin again after electrifying.
2. Then put some rosin and solder on the sandpaper. After the electric iron is electrified and heated, it is rubbed repeatedly in the rosin and solder sandpaper until it is bright.
In order to solve the problem of black hair of soldering iron, we can make a small soldering tin cylinder (which can be made of small metal cans and bottle caps). Usually, the soldering iron head is immersed in the tin cylinder to prevent the soldering iron head from contacting with air.
Or you can buy a new soldering iron head