I have addressed this in the past with iFly off line. They need to have a "clear TFRs" menu option. They didn't think it was necessary because they believed all TFRs have expiration dates and they would just time out.
I'm here to tell you (and them) that the many fire fighting TFRs out west are "till further notice" and have no expiration dates. They stay displayed on the iFly forever or until you do another TFR update.
IFly can talk you thru a procedure to get rid of them now involving removing the SD card but they really need to provide this "clear all TFRs" function.
Steve