What do I fill the empty portion of a longbox with?
 

Basic question; figured this would be the right place to ask.

I finally got my comics into a longbox, but it's only about two-thirds full. What's recommended for filling the rest of the box to keep the comics propped up?

Books lain down flat to prop them up.

That's seriously the only way I've ever seen it done, though I'm sure an official "book stop" guide exists.

Finally got it with two nicely sized shoe boxes and some bubble-wrap. Everything's flat.

I think I read/watched too much on storing and protecting comics tonight. All I want is decent-looking reading copies, but now I'm eying that box like, "Holy shit, these things are going to burst into flames any minute. I need to put them in a bank vault! The world is out to give them creases and mildew."

Well, let's face it. It is.

when i was heavy into collecting comics (I do digital now!) there was an easy solution to this: use multiple longboxes of different lengths.

I had full-size long boxes, a box that was half size and I think one about 1/3 size. I'd transition the books through these boxes accordingly.

Of course you have to be buying a lot of comics for this method to work.

I find that MORE COMICS works better than anything. :)

I use old textbooks, mostly. I own a lot of heavy Physics books from my undergrad, and they work great.

A smaller box sitting on its side with the bottom facing the comics.