Just in case anyone doesn't know about this.... BTW this is not advertising so stay back Trolls, this is for Double XP. For those who don't believe go check for yourselves, I have even bought a pack myself unknowing of this at first.
Call of Duty and Activision have teamed up with some companies to better advertise the game and food/drink products. What this includes is Mountain Dew and Doritos.
If people find Doritos or Mountain dew cases/bottles that have the Double XP on the box/bag/bottle they will find a code inside that gives you Double XP in game.