Never let it be said that smart companies can't ride a popular political tack to lower costs - Coca Cola is going to save a ton of money by not painting their cans, and get "street cred" for helping "save the planet":

I assume the consumption only increases through time, but let's take the daily 2007 numbers from Global INForM Cases Sales database: The total number of Coca-Cola cans sold per worldwide is 67,873,309. Diet Coke and Coke Zero sold 35,387,241, while My Coke sold 103,260,550. Yes, that's all per day.

Now consider the savings in paint neither bought nor used...