With the cost of blades, I straighten mine. BUT, I have a very serious block of steel to clamp them to, with the bent end suported on a piece of 1" hardwood. Put enough pressure on the clamp to bend them in reverse, then smote hell out of them with a 6 lb hammer. Not easy, but it works and I've never had one break afterwards. If you heat them you will likely have a very soft piece of scrap afterwards.