Originally Posted by Gypsiwoman
Softer pencils should be sharpened by hand because it is gentler on the lead. However I understand when you have a set of 120 pencils, hand sharpening isn't an appealing option. Here's a compromise. Sharpen your pencils 3/4 of the way by machine, then complete sharpening by hand. Remember to allow the electric sharpener to cool off after 3 - 5 pencils or you will melt the wax.
I understand you can tuck them in the freezer and let them sit a bit to harden the leads for sharpening. I haven't done it though. I sharpened all mine by hand...with a blister on my thumb to show for it.