Trouble keeping iron tip clean

[bool]

Are you all using metal or ceramic tips?

[anotherjim]

Ceramic Bool? New to me. I mean, ceramic is a heat insulator?!

BTW, Wet sponge -  it isn't soaking wet, just damp. Trick is to wet one end and it'll soak through, wipe tip across the dryer end. I keep one of those ubiquitous drinking water bottles to top the sponge up with.
Was always taught to never-ever use abrasive on soldering iron tips. Place I worked once had hundreds of Weller soldering stations with tips that had little magnets at the iron end - that was the temperature control. When it got hot enough, the magnet reached Curie point and switched off causing a sprung contact to break the element feed. Fairly expensive tips those.

[Rob Strand]

Re the sponge:  Ideally the hole or deep slots are used to get rid of the crap and the top surface is supposed to be kept clean and used to shock the oxide off the tip by lightly touching it before soldering.   Not many people use it like this.

[stringsthings]

I've got a very old Weller that is still going strong.  I think it uses those little magnet ends for temp control.
I've only used leaded solder and I use a wet sponge.  I have tried to use the brass cleaners, but it really shortened tip life.
I'm guessing brass cleaners work better with lead-free solder.

Here's a tip for wet sponges that I recently picked up on:
Cut a small circular hole in the middle of the sponge.
When you wipe off the tip, the solder bits will fall thru the hole and not remain on top of the sponge.
  ( be sure there is a good surface under the sponge so you don't start any forest fires  )