technique for trimming fat off brisket

Hi all;

I've done a couple cryopak briskets.  I've tried to follow your
directions, re: trinning fat to 1/8" to 1/4".  It's the hard,
yellowish fat.

I've just been using a sharp meat knife to try and slice it off, but
it's not working well.  I either go to deep and cut through the fat
into the meat, or spend way too much time scraping off thin layers of
the fat, and not getting it down to thickness.

Is there a trick?  A proven method?  Or is it just me?

Thanks a heap,
-Zz