Like everyone else said, use a thin blade like a hacksaw, otherwise it's going to splinter and possibly crack. I don't know if you've ever gotten a splinter from a composite hockey stick, but it's much worse than a wooden splinter because it's smaller and more likely to get infected.
Composite splinters are the WORST. They hurt ten times worse than wood and get lodged deeper because they are thin rather than a chunk. One time I got one on the bench and had to gouge out the skin to keep playing. Absolute worst feeling in the world.
Hacksaws and blades are cheap...you can get a hacksaw and mitre box for $15 brand new.