These are your camera masters. Not only should you not try to trim them, but you should have them on at least two backups.
If you really, really, really want to ditch some of them, every take is stored in its own folder so you can try erasing the takes you didn't use. I really, really, really don't recommend it, though. It'd be like burning your 35mm camera negatives just because your store room isn't big enough. You spent the money to shoot, crew and generate 280GB of RED footage; you really can't afford $250 to buy two 500GB drives to store and backup your camera masters?
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