So your big brass bed is in need of a makeover. Make an estimate of your budget and either start in on a DIY refinishing project or call up a local refinishing company. Check whether your bed is solid brass or brass-plated; the two materials will require different refinishing. Also, keep in mind that you can "redo" the look of brass with exhaustive cleaning and polishing, but you'll have to leave any replating to the professionals.
Painting a brass bed is an ambitious project, but you can you achieve excellent effects if you carefully follow all the necessary steps: cleaning, pretreatment, priming, painting and topcoat. You may wish to practice first on a smaller brass item, such as a lamp, before moving on to your brass bed frame or headboard. Because brass, like other copper alloys, is subject to corrosion, it's necessary to pretreat the metal before directly applying paint colour. Remove any oil or soil with a thorough cleaning. Sand the surface to remove any corrosion. Apply an epoxy primer and let it dry before applying your chosen shade of paint. Once the paint has fully dried, apply a clear polyurethane topcoat for a long-lasting and durable finish.
If you have a solid brass bed and simply need to restore its original lustre, try intensively polishing your bed frame. Give the frame a thorough cleaning with the finest-grade steel wool you can find, preferably 0000, to remove debris, dirt and corrosion. Use paint stripper sparingly and follow with high-quality brass polish or jeweller's rouge. After you've buffed the finish to its optimal shine, decide whether you wish to apply polyurethane sealer. Doing so will seal in the sheen and require less maintenance. However, some find the polyurethane gives a cheaper-looking finish that becomes dull over time. If you don't add any topcoat, you'll need to regularly clean and polish the bed several times a year to maintain the pristine and natural shine of the brass.
If your brass headboard requires a major overhaul, consider bringing it to a professional metal finishing company. If you have a solid brass bed, a professional may be able to restore its original beauty through intensive polishing, offering a full range of lustres from highly shiny to antiqued matt.
You may find that your bed is plated and not solid brass, easily discernible by the "magnet test"; solid brass is not magnetic. In that case, you may choose to replate the bed, either in brass or in another metal, such as nickel. The replating process must be undertaken by professionals, involving submersion in an electrically-charged bath.
Even if you decide you'd prefer a painted bed to any brassy finish, you may still wish to consult with a professional. The scale of the painting project and the intricate design of many brass bed frames can make drip marks difficult to control for inexperienced painters. Ask for estimates at local auto body painting shops.