The best way to protect your finished Yupo paper painting is to keep it away from sunlight. The UV rays of the sun turn the white Yupo paper into yellow, which can damage the overall quality of your painting. Similarly, you should store your painting away from moisture after waterproofing it.
You can frame your Yupo paper painting just like a traditional watercolor paper artwork. This will ensure that contaminants like dust and dirt do not accumulate on your painting. Hence, your artwork will stay protected and last for a long time.