I bought a Fjällräven Kånken and used it for a trip to Japan. After a few days, it was already dirtier than I expected. Unfortunately, the maid (unsurprisingly) didn't know how to wash it properly (well, neither did I). It now has some white spots and streaks, presumably because the maid used a brush to get rid of the dirt.

What dyes can I use to restore the color of these faded spots, or to just color the entire bag? There is a round rubber patch right in the middle of the bag - will the dye affect this area too?