Yes, you can store paint in a Ziploc bag that keeps car mirrors clean and dry. Ziplock bags generally prevent rainwater or snow from touching the car's windshield. This is why ziplock bags help the color last. Most of the time, it is seen that fog, rainwater, and snow touch the car mirror, which quickly discolors the car's side mirror. For this, if you want to keep the paint on the car mirror, use a ziplock bag on the car mirror.