I have a 48W ZD99 Solder Station. The protective coating on the iron's tip is starting to peel/break off. I believe this is due to a combination of moisture in the air where I live and incorrect care for the iron on my part. (I started using it before I knew that applying flux and tinning it would keep it in working order.) The current state of the iron's tip can be seen in the image below:
The slightly lighter area is where there is still coating. If you look carefully, you can see the ragged line between the coated and uncoated areas.
I have read soldering tip issues and the answers thereto, which suggest that it's possible to get something called "tip activator" for recoating tips and that it works reliably well. Assuming that I can't buy any from the stores I usually go to, what's my next best option.