A Lecture on Soldering By The Soldering Craftsman 1-10

Iron head cleaning-up is one of the very important jobs involved in soldering, which is easily to be overlooked. There may be some oxidized tin and flux residuals remaining on the iron head. If the iron head is reused without being cleaned, cold soldering will occur or solder pinnacles will come into being, both of which are classified as “unqualified”.

It is essential to clean up the iron head each time before using it, by a piece of sponge dipped with water. Normally, an iron stand is attached with a piece of sponge dipped with water. If the water is so excessive that it drips, the temperature of the iron head will go down drastically when it is cleaned, like it is put directly into water. So it is recommended that sponge be used in such a state that water cannot be pinched out from the sponge by fingers.
And it is also recommended to cut out a V-shaped trough or a round hole in the sponge so as to have convenient sides or corners for iron head cleaning-up.