I love my Grafmatics to death because, unless you are REALLY stupid and cycle through all six slides, you really can't screw up with unintended double exposures. And being able to prepare 6 sheets in one package instead of 2 is awesome. I always take 3-4 of them on my trips.
The bends can be straightened relatively easily; what I do is take a pair of pliers and slowly & gently straighten out the tips; then, if the pliers have pushed down on the slits so that you now have a tight entrance for your film, just take a screwdriver or an exacto knife and spread it out a little. I think it's better to keep them as straight as possible, since having the bends may cause more problems (getting stuck, bending more septum's, etc.).
As for cleaning, they're just metal; I'd wash them with dish soap in hot water :LOL:
One thing to remember: unlike normal holders, once you "set" the film for exposure (take the slide out and put it back in), you can't "unset" it… you have to take the shot, or move onto the next frame. This can be a HUGE problem when you're working (like me) with a barrel lens on a Speed Graphic, because once you set the film for exposing, you can't (easily) change the shutter speed any more, because that involves letting light into the camera, and there's no way to shield that from the film as you could with a normal holder.
The only way to work around this without wasting a frame is to cycle through all the film and come back to the frame number you were at. So beware; "set" the film for exposure when you are absolutely sure you're going to fire that shutter :-)