Annoying Habit?

Hey I need help with telling someone that they have an annoying habit. I work in a corporate enviornment with cubicles.. so least to say that we sit very close to one another. Now I am usually a pretty friendly person but I hate people with annoying habits. This person sits behind me and I can hear this slup and crunch on ice all day. This drives me insane along with my co-worker who sits beside me. How can we get this person to stop chewing ice all damn day. Please help.