Dyes are items that can be applied to any armor except jewelry. They cannot be applied to weapons. In previous Blizzcon events, it has been stated that some Dyes will only appear in the higher difficulties. There are also dyes that are designed to either make the item have no color or remove any dyes previously applied from the armor. There are a total of 24 different dyes that can be used to make any armor a specific color or even invisible.