Here's my secrect color for the yellowed lines on the speedometer and tach. Sharpie Neon pen in Orange. I throw on my magnifying glasses and slowly draw over the top of the yellowed lines. Two or three times allowing a couple hours in between coats. The color is bang on perfect to the Orange/Melon color it originally was. I used a bunch of junk 120 Rallye speedos and an NOS unit to find the color that matches perfect. Now everyone can freshen up their 71-74 B Body Rallye gauges for hardly any money. Just time.