A brass bed frame in good, shiny condition is something to be proud of. Brass does tend to tarnish so it needs constant attention. If you have a brass bed frame that has had no attention, it will take a lot of effort to resurrect that soft golden glow.
Identify What is Brass
Before you start working it is a good idea to make sure you know which parts of the bed are actually brass. If possible, take the bed apart so that you can work on one piece at a time.
Cleaning the Brass
With long-established brass tarnish, the chances of getting a decent result with standard brass polishes are not good. You will need to mix an acidic polish that will dissolve the tarnish and expose the raw metal. A very effective homemade cleaner is a mixture of mayonnaise, vinegar and lemon juice in the ratio of 1:3:3.
Apply this with a soft cloth and rub it hard. The tarnish will be dissolved away quite quickly and the acids will bring a good shine to the brass. Wipe the mixture off the brass with a clean damp cloth and then polish the brass with a commercial brass polish.
Brass polishes often contain a tarnish inhibitor which is left as a thin deposit on the brass. Every time you polish the brass it will shine up easier than it did the time before.