Brass Outdoor Lighting

There is a stanbdard cleaner for brass used by military guys, because they are required to keep all their brass spit-polish/mirror clean. Used to be called "Brasso", but I’m not sure if this specific brand is still available. Once you get the brass clean, consider some kind of anti-corrosion treatment because brass generally gets corroded very quickly.

If its rusted it’s a brass-effect coated base metal not brass. Brass is non-ferrous and doesn’t rust; it does however oxidise which discolours the surface and if left too long will result in pitting. You can check which is which by simply rubbing a finger over the contaminated area. If the mark left on the finger is reddish-brown it’s base metal; if it’s grey-black it’s brass.

If the fixture is in fact base metal with a brass-effect coating, there isn’t much you can do except change it. Conversely, if it’s brass use a proprietary metal polish (obtainable from any good hardware store) to clean off the deposits and then burnish with a soft dry cloth. Repeated burnishing builds up a patina on the surface of the metal which, over time, both retards oxidisation and provides a much richer colour to the metal.

If you are reluctant to keep cleaning and burnishing the fixture, an alternative is too clean off the brass as above and then coat the metal with clear lacquer. If you chose this route, make sure to wash-off any residue of the cleaner with warm soapy water and then allow the metal to dry thoroughly before the lacquer is applied. Lacquering is a viable option but in my opinion the appearance of burnished brass is well worth the little extra work involved.

NB. If it is brass, whatever you do, DO NOT USE a commercial rust inhibitor. These are normally phosphoric acid based and can cause permanent discolouration. Similarly, do not touch brass with sandpaper or emery cloth. Brass is very soft and both will mark the surface of the metal. Subsequent removal of those marks would entail either machine polishing or extensive hand-polishing with a fine graphite based abrasive paste.