Did you put a new blade in your paper trimmer last week and now it seems to be shreading your cardstock? Or did you go to scrapbook class with a bad blade because you forgot to change it? Or are you just tired of having to change your blade every other week?
Here's my solution:
Turn it over and on the back side sand all the edges smooth.
Now keep in mind this is a temporary fix. You will need to replace your blade eventually. Also, if you need to use this tip on a piece of colored cardstock you will need to ink the edges with the matching ink pad if you don't want the white core to show.