You'll notice that I'm working on my Scandal Haruna signature Telecaster. This is a cheap Indonesian guitar that obviously didn't go through a very good QA process, and mine had rusty frets right from the factory.
The Planetwaves system is basically just a few sheets of extremely fine-grit sand or fiber paper combined with a cutout cardboard fret guide to keep you from sanding your fretboard by mistake. Extremely simple, but that pleases my inner engineer. It also pleased my wallet, because the system costs about $5. It almost seems like something that cheap couldn't possibly be effective.
But it is! It may be a bit hard to see, but first, you should be able to make out that the left half of my frets above are mirror-like and silver, while the right half are still dull and brownish. Yep, I was about halfway done here. Also look at the paper - those black marks on it are rust from my frets.
This is the finished product. It's perfect! I really could not be happier with this system. It does restore your frets to a mirror shine as it says it will.
I later did the same to my Japanese Jazzmaster, which I play most often and its frets seem to dull quickly for that reason. It was a little harder to get them to a mirror shine, but I think that's because of the nature of their dullness, which is from tiny microscratches that accumulate through playing. This system seems to more easily handle dirt or rust than regular fret wear, although it did still help even on the Jazzmaster.
It does take some elbow grease. If you try this, don't give up after just wiping your frets a couple times. You really need to get in there and scrub back and forth vigorously. But the results can really be satisfying.