Shaped Pencils

My daughter rec'd box of crayons wonderful made in the Czech Republic for his birthday. They produce rich colors and beautiful, but how to refine?

You should be able to use a pencil sharpener ordinary. You can also go in an art supply store and try a few different sizes to see which works best. I just use a regular pencil sharpener with two holes and it works very well for me.

with a knife

try a knife or a blade