Quote Originally Posted by Unregistered View Post
just discard the unit or is there some special place to sell them?
Simply sell the unit as you would always do it. Gold rarity units and above will give you additional rainbow crystals as mentioned above. Keep in mind that event/TP units drastically reduce the amount of rainbow crystals you get. I don't know the exact amount, but I do know that golds and plats net you a value below 10 and event blacks give you 20.