I used this on my Wifes white gold wedding ring that had yellowed a little, i also used it on my Titanium wedding ring that had gone greyish.
it brightened both of them up and i only did it quickly.
Good product, i used this on a 2013 Gibson ES-335 DOT
The frets were just too tall for me so i decided to lower them and make them more like my SG, i filed them down with a fret levelling file and then re crowned them with this tool.
Its not for the feint hearted when you start messing with a very expensive guitar but was easy enough and the tool made the job simple.
The think i liked was that the file came with the different grades of sandpaper to polish up the frets afterwards.
I spent about 10 mins crowning the frets and then about an hour polishing with the sandpaper, working up through the grades to get a nice finish.