Why use the Hakko 599B Tip Cleaner over the conventional damp sponge?

One of the biggest reasons why is because the Hakko 599B Tip Cleaner can remove oxidation buildup from the tip without removing the solder, or exposing the tip to thermal shock.  The soft brass coils of the Hakko 599B allow oxidation to be removed without detrimental effects on the tip, while leaving a light coating of solder behind to help prevent further oxidation of the iron plating.

When using a damp sponge, the minerals in the water and any debris on the sponge itself that come in contact with the tip can lead to additional buildup.  The sponge also removes the solder from the tip exposing the iron plating to the air and the water of the sponge.  Iron, water, and air all come together to make iron oxide, or rust. Using a wet cleaning sponge will also expose the soldering tip to thermal shock  from an immediate drop in tip temperature.   This is why it is important to immediately re-tin the tip after cleaning.  The Hakko 599B re-tins the tip as it cleans, and never exposes the tip to any water or minerals drastically improving / extending the life of your soldering iron tip