ex problems?

My ex and I go to the same school. He's a grade above me and I rarely see him. I want to ask him if we can be friends because for two years we have been in a pretty awkward stage. He won't respond to his Facebook, I've left him notes before but he told me they freaked him out. But I'm terrified to talk to him in person. I don't know how to ask him. Any ideas??  I'll take anything. Thanks guys.