I need to store mine upright & out of reach of the kitties. I can't put them on the floor because the cats tend to pee on them. (yuck).

I'm worried about them getting warped. Any suggestions on keeping them straight?

Use a clothes hanger with clips and hang it in the closet. That would help.

I keep mine under the bed... could you hang them behind the door...?

How about between two stiff pieces of card taped together on three sides so you can slide it in on the open side? I have 3' x 2' stored like that til I get my new sewing room (we're converting the attic - no room for it at the moment!)

Can you store them behind a large piece of furniture like a dresser?

I hang mine on a nail inside the pantry door.

I hang mine by a nail, also, and they stay perfectly straight!

I store mine behind the cabinet I have my quilting supplies in.

I was lucky. Mine came in a cardboard box, so I keep them in that. But I place the box along a dresser and the wall to keep it upright. I have a cat also and I thought hair balls was bad.

I have them hanging on a nail on a wall, works great for me.