You need to "tin" your tips, that is keep them covered with a thin layer of clean solder. I normally touch a piece of solder to the tip then wipe it off lightl

You need to "tin" your tips, that is keep them covered with a thin layer of clean solder. I normally touch a piece of solder to the tip then wipe it off lightly with a clean, dry rag just before I unplug my iron each time I use it. Doing it after you finish helps insure against corrosion in storage, plus it is all ready to go the next time.