pplummer's technique for removing the old whisker is excellent AND it is a "safe" way to do this. I cracked one stainless channel for one of my windows by trying to pry out the old whisker (luckily I had one spare). I did not recognize that those pieces were welded. As I think I posted above, I took about 4 hours per channel to slowly and carefully remove the old whiskers (patience and a Dremel tool helped a lot).
