if you mean for the prior year return got to tools, options, general and check off show previous tax year color

I have just been using a crayon, but your way sounds much simpler and that way I don't have to scrape off my computer screen when I'm done 😬

Why change your process at this point?  Keep the crayon. 

at least with the crayon you can pick your color - otherwise you are stuck with the greenish color.