Have no idea how I got this to post but here is a photo of the crates my DH built for me.

Beautiful crates. I would use them.

Some of my shelves are varnished, others not. The only ones I covered with contact paper are the yukky particle board ones that I bought by mistake and didn't take back.

Consider having a piece of Plexiglas cut , it does not need to be as deep as the shelf only a few inches by the length, that will elevate the fabric boards you are using. If you intend to place fabric directly onto the shelves with the boards .. have it cut the length and depth of the shelf.

My DH made shelves for my UFOs in the guest room closet out of pine boards. I used Elmers Glue and put scraps of batting on the bottom and sides of the shelves to protect the fabric from acid stains. When the stacks of UFOs reach the shelf above, I lay a piece of batting over the UFO to protect it from the bottom of the higher shelf. Been that way for several years now with no problem.

Nice of DH to do this for you.
peace

I would put a clear coat of varnish. A thin coat should do!

These boxes are beautiful. Enjoy them.

I wouldn't worry about it unless they are going to be sitting there for years on end. I store my larger yardage pieces in cedar trunk my DH got for me when I first starting sewing and they are still fine. I also remember my mother and grandmother storing all of our quilts in a cedar chest for as long as I can remember. I now have that same cedar chest with some of my quilts in it now.

Jealous! It's awesome.

I have a number of items in my cedar chest and they are still fine (no quilts). The only thing that has any stain on it is my wedding dress, which is velvet, because I didn't have the foresight to wrap it in acid-free paper.