Instructions
Play through online games to level up to the primary stage of level 70. Go to your "Combat Record" screen to enter "Prestige Mode." Prestige mode will cause all your weapons, perks, money and other items to reset so you have to start from scratch.
Continue to rank up through each prestige level. There are 10 prestige levels that require completion of different challenges, located in the "Challenges" menu. Challenges are completed through online play and require you to be well versed in different weapons, items and perks.
Finish the 10th prestige at level 70. Once you have completed level 70 at the 10th prestige, click on the "Call-sign &Killstreaks" option and select "Emblem."
Flip through the pages of available emblems until you reach the prestige 10 emblem of a spinning gold skull. Select and purchase the emblem. Once purchased, the emblem should appear on the top-left corner of your screen as your call-sign.