How do you get gum out of a white shirt?
In order to get rid of chewing gum on a white shirt, first wash the shirt. Then rub the shirt against ice cubes. This is done to harden the gum, and later easily scrap it off with a dull knife. See more details at http://www.ehow.com/how_113052_remove-clothing-stains.html.
Try to freeze the shirt and then pick the gum off after it hardens.
Wash it in cold water and pick off as much of the gum as you can before you wash it.