My sun visors were badly discolored.....the top of them was especially bad. I took sand paper to the top to get some of the "brown" deposit off. And then I sprayed the whole visor with Meltonian Nu-Life Color Spray for vinyl, plastic, and leather; Code is 649 Vanilla; no bar code, but bottom of 4.5 oz spray can says “08178 Vanilla” . The cost of this 4.5 oz was $7.00 through a shoe repair shop.
The visors look very nice now, and the color is a close match to the underside of the hard top. Have not done it yet though.