Declutter Advice, Please Help!!

We are decluttering and not having much problem. It has been really easy. Toys are way down. I have my clothes down to where they could fit into 1 1/2 suitcases. Everything is gone that we don't need or use.

BUT..................

I am having a huge problem with the homeschool items! I can't seem to get rid of any of it. I have 4 shelves full of books. A chest of drawers full of supplies. A bedroom full of anything else that we would use for homeschool.

WHAT DO WE DO??

HOW DO I DECIDE WHAT TO KEEP AND WHAT TO DONATE??

I cannot seem to get my head around getting rid of any "school" items. Especially with the thought of us going to go off-grid with in the next few months. I just think that I will need it all. How do I figure this out??

HELP!!!!