To trim and prepare the sponges, I used a wooden straight edge from a home improvement store that I had lying around, and a utility razor knife. A metal straight edge would be better but I didn’t have one that would work well for this. Something to draw markings would be handy but not required.
Using the old sponge and taking measurements from the solder station, I found I could cut one sponge into two well fitting sponges for my needs.
I mark the sponge for cutting, used the straight edge on the side I want to keep and pressed it firmly down to compress the sponge a little, and then I dragged the utility knife along the edge. When you do this, make sure all your fingers are out of the way and that you are cutting on a surface that the knife won’t damage. You may have to make a few passes to cut all the way through. Repeat for all cuts that are needed. Discard sponge remnants in the trash.
I took the new sponge and compared it to the old sponge to make sure I was close, then I sized it up on the solder station. A little trimming maybe needed, and it is fine if it is a little small as it will expand a little when it dampened. The solder station sponge trough is deep enough to hold the wet sponge, so when I dropped it in it was be hard to remove. I just use the edge of the utility knife and slide it into and edge and pried it out.
The sponge will need to be scored so that it will have slits that allow the solder iron tip to get dragged within. This allows one quick pass to clean almost all sides of the soldering iron at once. Using the straight edge and utility knife again, I lightly scored a line about every ¼” completely across the surface of one side of the sponge. I found it better to press lightly and make multiple passes to get a good depth than to cut all the way though in one stroke.
I soaked the flat dry sponge with water and watched it grow.
I dropped it into the solder station and I was ready for some marathon soldering.