The Treasure of Duplicates can be opened every day and always contains a nice random prize.
To open the Treasure of Duplicates you must have 14 stars (common stickers are worth 1 star, uncommons are worth 2 stars).
When you open the Treasure of Duplicates you receive the reward and some of your random duplicates disappear (for a total of 14 stars)
The counter (in image 1/14) tells you how many duplicates (common and uncommon) you have, in this case we have only 1 star.
N.B. duplicates will disappear from your albums only if you click on TRADE.