Chill the brisket until firm, but not frozen
Place it fat side up on a cutting board
Use a sharp boning or trimming knife
Remove any loose, thin, or ragged edges
Trim hard, thick exterior fat down to about 1/4 inch
Leave a thin, even fat cap on the top
Remove any large pockets of hard fat between the point and flat
Trim silver skin and thick membrane from the meat side
Square off the brisket for a more even shape
Remove any thin corners that would overcook
Smooth the edges so the brisket has an even thickness
Pat the brisket dry after trimming
Save trimmed fat for rendering if desired