I got a Diet Coke from a vending machine today. The can had a bright green tab on it.
Now, I'm no can enthusiast, but I am a curious person. So I tried to figure out what the green tab meant. But there's nothing on the can that seems to indicate what it's about. (There's a little logo for The Heart Truth, but no mention of the green tab.) I did a quick Internet search, but still found nothing. (The closest thing was some promotion Sprite did last year where they would donate money to Habitat for Humanity for every green tab collected.)
Then I found this website and figured that if anyone knows, it would be you guys. So what's the deal? Did I win a million dollars?
My first thought was also a "going green" promotion similar to the Sprite cans last summer. In fact, it was one of the only cans I remember to feature a design element on top of the can - besides the world cup soccer cans from europe. Interesting find.
Sometimes states that have a "deposit" where you can get like 20 cents per can will have different color tabs to help keep people from other states bringing over cans they did not pay a deposit on and making tons of money.
Iowa is the state that comes off the top of my head.
I know Pepsi did this around the time of the Star Wars can promotion - I was trying to collect a set of those also.
Not sure if this is why you found a green tab - or even if the states still do the deposit on cans.
I've collected cans for many years - run the (very outdated) popcan.org website. I've once wanted forums & a site like this - glad to see this one here, and plan to support it as much as possible. ***UPDATE*** I May be trading soon! My Collection will finally have a home!