
There are many DIY cleaning methods that you can use to polish and restore antique brass pieces. But before you start scrubbing away, it's important to understand what causes tarnish and how to remove it without ruining your metal items.
First, determine how old the brass is. Also, what finish it has. You will need to remove the varnish from brass lacquered before you can use a cleaner to remove the tarnish. You can remove tarnish with mild soap and water if it isn't lacquered.
Next, you need to find an acidic substance to remove the tarnish from brass. While tomatoes and lemons are excellent options, you could also try vinegar or mustard. A thin layer of any of these will be enough to help remove tarnish from brass. Allow it to sit for around an hour before gently rubbing it off with a toothbrush or soft cloth.

Another good DIY tarnish remover is toothpaste. Sean Parry, Neat Services' cleaning specialist, said that toothpaste "reacts with acid present in the tartar."
Bougere suggests that you rub an antique brass piece with a lemon wedge or rind for about 10 minutes. The combination of the lemon's citric acid and the salt's abrasiveness can be quite effective at loosening and removing tarnish, especially on more delicate brass items.
Mixing lemon juice with table salt can also be used to make your own paste. The salt and lemon juice should be combined until you have a thick paste. Apply it to brass objects, and let them soak for at least an hour before cleaning them.
After scrubbering, rinse the brass and dry it using a microfiber or paper towel. You may need to repeat this process several times, depending on how much tarnish is still on your brass.

You can also use equal amounts of flour and vinegar to clean brass and copper that have been exposed to oxidation. Let the mixture soak for about an hour, and then scrub it with a toothbrush to loosen the tarnish.
A natural, organic salt-based product is the best way to clean brass that has been badly tarnished. Flitz Instant Brass & Copper Tarnish Remover is a fast, safe and effective way to remove copper tarnish.
Spray-on tarnish cleaner instantly dissolves, lifts, and removes heavy tarnish, calcium, rust and corrosion. It is safer and more effective than traditional acid-based cleaners. It's safe to use indoors and outside on copper brass, aluminum and glass.