Hi I am new here, and am a beginner at painting, I just got into painting and am starting with some paint by numbers, I have been working on one, but have found another I really like and might start on before I am finished with the first. My question is there anything I can do to keep the little pots of paint from drying out if I take a while to go back to the first? I had read a couple of reviews of these sets where people said they took a long time and some of the paint dried out.. I want to try to keep them fresh. Thank you for any help, I couldn't find much about it and thought I would ask someone who knew more than I do!