Activate Cold Storage's first ability twice by paying 6, exiling Sanctum Gargoyle and Dockside Extortionist from the battlefield.
Activate Cold Storage by sacrificing it, returning Dockside Extortionist and Sanctum Gargoyle from exile to the battlefield.
When Dockside Extortionist and Sanctum Gargoyle enters the battlefield, they trigger.
Resolve the Dockside Extortionist trigger, creating at least ten Treasure artifact tokens.
Resolve the Sanctum Gargoyle trigger, returning Cold Storage from your graveyard to your hand.
Activate ten Treasures by tapping and sacrificing them, adding 10.
Cast Cold Storage by paying 4.
Repeat.
If opponents control eleven or more artifacts and/or enchantments, this combo nets infinite Treasure tokens and colored mana.
This delightfully crafty loop relies on Dockside Extortionist to generate a flood of Treasure tokens when entering the battlefield, provided your opponents have brought enough artifacts and enchantments to the party. To sustain the loop, Sanctum Gargoyle acts as your recurrent retriever, pulling Cold Storage right back from the graveyard to your hand every time the artifact is sacrificed. Speaking of which, Cold Storage does double duty here: it safely tucks away your creatures in exile before you pop it for its ultimate return trick, and its reuse is entirely funded by the massive mana reserves your Treasures provide.