Suggestion for Hextech Crafting
Allow Chests to be changed into Keys, at 2 Chests = 1 Key (or 3 Chests = 1 Key if that is too generous), and likewise allow 2 Keys to be changed into 1 Chest (again, or 3 Keys = 1 Chest if the original is too generous).
At the rate of 2 of X = 1 of Y, this removes any abusable actions and allows users with an excess of Chests or Keys to use them instead of constantly accumulating more then can be used.