A number of years ago, when Riddell used to do their reconditioning in San Antonio, the rep there told me that they had all sorts of problems with rejected (old, damaged) helmets coming back to them. People would actually take them out of the dumpsters and they'd get them back for reconditioning again.
They started to cut a larger ear hole, but the helmets still got taken out of the dumpsters.
So, they started to cut them in half. Problem solved.
Whatever you do (making them as give-aways to boosters is a great idea), just be sure they are no longer usable as football helmets. Remember, the most expensive part of the football helmet is the liability insurance!