What’s the best way you’ve brought the fender and quarter side marker chrome back to life?
Remove them and polish with #0000 steel wool (with or w/o some liquid or paste metal polish). then polish again with your choice of a good wax. But… if they are pitted and/or hazed, none of that is going to improve or come off and you’ll only be able to take them so far.
You did not tell us what year Cougar you are working on so this is just in case information. If you have a 69 the bezels are available in reproduction form and are not very expensive. If you have a 70 then only the outer rim of the bezel will have exposed chrome, the inner areas have a silver/argent color paint on them. If you remove that paint there is chrome under the paint.
Randy Goodling
CCOA #95
if they are a 68, flip them upside down, then the better chrome is on top
1968 are also reproduced but you have to reuse the light sockets.