I put the worn out blades in with my paper cutter -- I cut shelving plastic, wrapping paper, etc, with these blades until they are really dull. (DH is allowed to use the paper cutter -- but he prefers me to use it). I have 4 cutters -- the 18 (this is my ripper and my circle size), the 28, the 45 and the 60 (I use the 60 the most so I buy the most blades for this one). Before a blade goes to cutting paper, I take it apart, clean the blade and turn it around -- it usually cuts better for a while.