It's time to stop cleaning your fingertips with classical methods ...
The use of copper balls instead of water and sponge used in the cleaning of the soldering iron reduces the surface tension (static electricity) that will form on the soldering tips, preventing oxidization. The soldering iron tips do not darken and the lifetime is prolonged
Thanks to the flux (resin) in it, you get high efficiency and high quality results in circuit soldering.
Copper and other materials are rapidly oxidized when compared to air, humidity and heat, so flux bound points must be applied to the surfaces before soldering. This oxidation occurs due to oxygen / air exposure to oxygen and becomes non-conductive, that the metal can not be soldered on the surface.
Oxidation on copper surfaces converts matt and orange color into a bright non-oxidized copper surface.