Much appreciated, guys.
I'll use both of these suggestions!
Might as well throw my two cents in since those two gave some weird ass advice imo.
No, running isn't the best way to get rid of a double chin. Having a double chin just means that you are fat and your body likes to store fat in that area. If you want to lose the double chin, you need to get leaner overall since fat loss can't be targeted. This is achieved by having a caloric deficit (ie. dieting). Cardio can help by increasing the deficit but there's nothing magical about running. It has the same effect as any other type of exercise.
Also the advice about using some sort of moisturizer to get rid of body fat sounds pretty amazing. I mean this is the holy grail that women have been searching for decades. A lotion that burns fat and tones your skin. In all seriousness though, some moisturizer isn't gonna do anything except give you a nice, smooth double chin. It won't go anywhere by applying some lotion on it, we're not talking about some rash here.
If you want to get rid of the double chin, get leaner still. That's the only thing that will work. I can guarantee you that.