It's how us creative types try to feel all worldly and crap.
I found a couple tutorials online on how to make your own mini plein air kit, so I thought I'd give it a shot.
Start with an altoids box (or that approximate size) and a block of white sculpting clay. Get the brand that you can bake in your home oven. (Fimo, sculpty, etc). You'll also need some glue and a can of white spray paint
This altoid tin is really a blank I bought years ago to do something crafty with and never did it apparently. I think I was going to use it for a scrapbook.