I am going to a plain air workshop in Sun Valley, Idaho in a few weeks. I'm extremely excited- a dream come true! Does anyone have any plain air experience and tips? I have purchased a guerrilla painter box and I'm wondering how the paint on the palette stays fresh inside the box since it is not air tight? I guess you are supposed to clean the palette after each painting session? What if I want to paint frequently on the road? How do I keep paint fresh and brushes, tools clean? Maybe I should switch to water mixables while traveling? Thoughts?