It would drop a single element at a time once per week per character. I have three characters and I run it 3 times. Once with each. I have a chance to get the Arc, Solar, or Void "Core", It's not a guaranteed drop. And you can get this drop up to 9 times. 3 per character( Or until you have one of each element per character) Another solution would be 3 drops per account with it taking whichever element is dropped for you off the loot table so no repeating drops. More common drops would be the same thing, but only usable on Special or Heavy weapons. Like if you have an Arc Sniper, but want to change it to Void instead. Those drops wouldn't be limited and could be turned in for rep. You also get a one time only drop(1 per account) that will let you change the element of an ALREADY elemental Exotic weapon to any of the 3 elements. Example- Invective is Solar, but you would love to have one that's Arc or Void. You can change that element only once. You cannot use this on weapons that are specifically designed for use with one element. Like you wouldn't be able to change the Element of a Zhalo Supercell, Necrochasm, Icebreaker, or Thunderlord since they are all designed with their elements in mind. This is my idea, but I know they won't do that.