I store my smaller paintings in cardboard pizza boxes. This habit started in college, when I recycled real, used pizza boxes to stash my artwork (I consumed a lot of pizza in the 90s). I used to think it would be really fun to stick one in an actual pizza box and hand it to someone. Actually, I still think that would be kind of fun.
Truth: it’s winter, I’m working non-stop, and my studio is getting out of control. I spent some time boxing up paintings today. I store my smaller paintings in plain, white pizza boxes. The boxes are perfect, because they are about 1/4″ deeper than my back-framed paintings and a small fits a 12″ x 12″ piece perfectly. Medium pizza boxes fit 16″ x 16″, and so on. My larger paintings are usually stored with cardboard strips and plastic bags.
Once the paintings are safely tucked inside the delivery boxes, I label them for drying/storage/shipping and stack them on shelves. No need to worry about messy hands, dust, pet hair or flying paint! I list the title, medium, size and date on the right corner, and on the top.
The boxes store flat and then I quickly convert them, as below. It’s really a perfect system for storing unframed artwork.
I wish pizza came in larger sizes; for lots of reasons.
Today’s cleanup  soundtrack is Joan Jett.
***