Six and Cloud Key on the battlefield (Cloud Key with "Artifact" chosen).
({1} magic symbol) available.
Steps
Cast Chromatic Sphere from your graveyard by paying ({0} magic symbol) and discarding Dakmor Salvage.
Activate Chromatic Sphere by paying ({1} magic symbol) , tapping and sacrificing it, adding ({1} magic symbol) and causing you to mill two cards and return Dakmor Salvage from your graveyard to your hand.