How to easily update outdated artwork from thrift store! I found a botanical print that I loved at the thrift store and painted the outdated dark green mat white. I've mentioned before that I spray paint mats from thrift stores. But in case you don't have any spray paint or if you just don't have the right color, you can paint it by hand, too. I just used some tape to cover the print (which was previously glued to the mat) and used some leftover off-white interior paint.