Brian,
This is definately something we are looking into at this time. We have the ability to do so when we sense the card is getting full, but having the option to clean or remove areas, even when there is room left is coming soon. We are actually working a graphical update page where you will be able to select on the states or even swipe for a flight path. Then install and remove by simply touch and choosing to install or delete. Stay Tuned.