begonia corms

I have just checked my overwintered begonia corms to find that most have at least 5-6 inch shoots. Do I pinch the shoots off or can I do anything?  Corms were stored inside in a paper bag and I have about 60 of them so really need to save them...Help!

I usualy lay them on a tray of compost to make roots then plant out when frosts have gone.dont know if this is the right thing to do but it works for me.