I used the fruit as one of the ingredients for the spring toss or yee sang. I usually try to keep the skin and not throw it away. They do come in handy for some evil ridding rituals.
What you can do is, boil the pomelo skin and leaves for a ritual bath that cleanses a person and repels evil. Besides getting rid of negative Qi, the skin of the pomelo when used in a herbal bath is also believed to help rid the body of wind.