To remove gum on your shirt, you can harden it with ice cubes or pre treat it to make it easy for it to come off. If you rub ice cube on it, the gum will harden and it will make it possible to scrap it off. You can also use the pre-treater and allow it to stay on the shirt for sometime in hot water before washing it. If the shirt needs to be dry cleaned then you can take it to a professional. See http://www.ehow.com/way_5367906_do-remove-gum-off-clothes.html for reference.