How can I preserve paint and brushes between projects?
I generally pour my paint into a smaller paint pail, like this: 



and then brush from there. They make liners for those pails, although I find they clean up relatively easy (most have a non-stick coating of sorts). They make pour spouts to making pouring easier, as well:



Depending on the size of the pieces and how many you can paint at once, I may just dip the brush right in the paint bucket, though. Get fairly high quality brushes, and be mindful of dirt and dust, and contamination isn't usually a big concern. When I'm done, I pour the remaining paint back into the big paint can.

As for storage, put the brushes, roller covers, and paint tray liners in a plastic zip-top bag(s), and put the bag(s) in the fridge. It will keep the brushes in good enough shape overnight, or over a few nights. You could give them a quick rinse before using. You'll probably want to wash them out after a couple of days, and definitely when switching colors / after priming.



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