Im having a bit of a dilema here There are a total of 30 silver keys in the the game but if you look at all the chests - they require more than 30 keys. Once you open one you dont keep your keys. I just used 25 to open the chest in Necropolis for the Badass armor but now i have no keys left to open the others except for one that requires 5. Are there more keys to find or once you use the keys they go back to their hidden spots?
Actually you don't lose keys once using them, the only time its possible to lose silver keys is opening the Demon Door in Bleached Bone Island