Steel leaders will do that after a few pike usually. I have never heard of a great way to straighten them. A good investment are titanium leaders such as teminators. They are very pricey about $15 each, but are worth it considering they will last a thousand times longer than a steal leader. They are actually cheaper in the long run if you look at it that way. I am a pike guide at a fly in lodge in MB, and still have one terminator I have used for two summers now, I have likely landed a thousand pike or more on it and the only thing that finally wore out at the end of this summer is the rubber protector on one of the loops, other than that its still perfectly fine.