Storing Paint for Plein Air Painting

It drives James nuts how fast the oil paint dries out in a Soltek easel (since it's not airtight), and what really gets to me is how it all slides down to one side of the palette when you're hiking if any of the pigments have some extra oil in them, so when you open it you get this big mess of paint soup to deal with. So... my latest attempt to solve this problem has worked out quite nicely so far: Airtight pillboxes.

I just set this, open, between my palette and painting on the Soltek when I'm working and scoop paint out as I need it. No need to put piles of every color on the palette, and that way there's more room to mix paint. I'm liking this a lot.