I've refoamed a couple of lansings now without a problem but now I have a pair of LE15A. A parrot ate some of one of the surrounds. The surrounds are not hard and crumbling or soft They are hard as old leather. I have used a razor blade in the past, it hardly seems up to this task. A box knife may remove the cork gaskets but if I leave the surround layer on the cone will this cause me trouble? It seems like you could make more difference in depth by where you position the surround (they don't come with lines drawn on them) then this thickness would make. Trying to remove this layer without skinning the cone is almost impossible. This is the first time I've had this problem but I haven't done dozens of them.