Changeable Motor Oil

Hi Chris! I love your videos. My wife has been telling me for a while to reach out to you and thank you for teaching me and providing me with the hobby that I absolutely love. So from the bottom of my heart thank you so much!!! With that being said I do have a quick question. I have been making this recipe for motor oil for a while now. Thanks to your videos. They always come out looking phenomenal when freshly poured. But I've noticed after a very short period of time, they lose all of the green hue and im left with just a reddish brown. What can I do to prevent this from happening? Or does this particular color have a short shelf life? Again thank you for being an excellent teacher. And please never stop producing videos! Aaron Baldwin Ocala Fl