I have a spare set of dash end vents (a.k.a. 'eyeball vents') for my 71, and would like to clean them up. They have a stubborn , greenish tarnish on them. I have tried a bleach solution, some tile and grout cleaner and gentle application of a brass brush. The chromed plastic still doesn't come clean. Any suggestions?

http://www.novuspolish.com/

I use their plastic cleaner and polishes.