Dunlop Micro Fine Guitar Polish 5410

These things are basically really fine grit sanding cloth. 8000 grit in fact. So you'd have to sand the frets with something more coarse to start with if they are corroded.
I use some wire wool and a fretboard protector first and then the polishing cloth.
Probably better for keeping your frets nice rather than making horrible looking frets nice again.

My frets were very dull and grimey, now they're shining!
One cloth is enough for a whole fretboard, you can clean the cloth and use it again but I guess they won't be as effective as the first use.

This is a very fine polishing cloth. I use it as the final step when restoring/polishing my frets and it works great. You can use the same cloth multiple times without problems.

Ju mer du polerar, desto lenare och blankare blir metallbanden.
Vilket i sin tur förenklar bends.

Bra för underhåll !