I too have not had any luck with these blades. I had a post going a couple of weeks ago and received all kinds of suggestions--none of which worked for me. I had bought 6 pkgs and opened three-not a one cut. However it is cutting the comic boards that I am using to organize my fabric. Don't know why that is though, it's thicker than the two layers of fabric I was trying to cut. Oh well, not all is lost. I won't buy more however and it is not convenient to return them. I no longer have the receipt either.