For chromework I use a metal polish called Autosol which comes in a toothpaste-like tube and even resembles an oily toothpaste. It works ok. If you cant find Autosol there are many similar products. Or failing that just use toothpaste!
Just remember to tape mask over adjacent paintwork and especially any rubber gaskets, which are porous and easily stained. These stains are hell to remove. Btw the grille is also quite easy to remove
However the anodised aluminium trim around the windows is much more problematic. Once the oxidization (cloudiness) has occurred, the coating has gone, and unless the trim is completely stripped back and re-coated there is not much that can be done to restore a truly OE finish
Apparently this mob below (patented process) have done fantastic work on W108 trim, but other platers have produced shit results
Electromold the most experienced surface coatings and metal processing in the Southern Hemisphere
Failing this if you're dedicated, you could tenderly use a 'deburring wheel' to remove the coating and then labouriously buff, which gets a super-shiny finish but also tends to highlight any scratches. To reseal, periodically coat with Incralac
This stuff might be worth investigating? Apparently very good for billet aluminium (heat resistant too) but dunno regards thin trim
::: Z O O P S Products, Inc. - ZoopSeal :::
Or use a soft buffing compound with some 0000 steel wool, then the Incralac
Or let sleeping dogs lie, as they say, and resort to regular car wax as a form of 'damage control'
Btw for the paintwork I studiously avoid using any polish or wax that contains silicone or polymers, avoid them like the plague imo. And keep your interior plastics away from Armourall! Try '303 aerospace protectant' (no silicone!) or, believe it or not, plain old vaseline