For some reason, the only way to get Treasure Keys is to farm those Ether Chests. Which honestly isn't very reliable but is your best bet. Problem is you get a lot of Special Ammo Synths which are obviously useless most of the time. Heavy ammo synths are useful for Ghorn but special ammo is not as everybody has Ice Breaker by now. What we need is a "discard" option are the ability to exchange them for more heavy ammo synths maybe for 50 glimmer like Ascendant Shard and Energy. I'm sick and tired of not having anymore consumable spaces as I have about 60 on each character.