When you go to straighten (mostly) them, use a heat source and get them just barely too hot to touch barehanded. Not so hot they burn. Wear leather gloves or wrap them in something. Then bend them slightly and hold for a few seconds. They way you straighten the nodes and internode spaces is exactly the same: apply heat and bend. You will just apply heat to a shorter length of space when you are working the nodes. Start at one end and just work your way to the other. Typically, as mentioned, it's best to do this straightening before you do the sanding. A little touch up straightening after sanding is fine, but get them generally straight first. They don't have to be perfectly straight to fly really, really well. Something about the natural taper and kinks off setting and I dunno whatall else, but they make great shaft material.