Clean the brass item thoroughly and remove all particles of dust from it.
Take a piece of cloth and soak it in acetone. Rub it firmly all over the brass item to remove any protective varnish that may have been used by the manufacturer. Make sure the acetone is completely removed. This is important for the antiquing process to be successful.
Wash the item in the warm soapy water and wipe it dry. Make sure there are no smears left on it.
Examine the brass item and decide whether you want a consistent patina all over or if you want it to be variegated.
Pour the white vinegar into a bowl and use the brush to apply the vinegar to the areas that you want to oxidize. For best results, the brass item should be slightly warmed, either by placing it for a few minutes in a slightly warm oven or leaving it in the sun for a short period.
Let the vinegar dry between applications. Reapply the vinegar until you have achieved the desired color.
Wipe the brass item with a damp cloth to get rid of the smell of vinegar and let it dry.
Using a clean cloth, gently polish the brass item. After antiquing, either let the aging process continue or seal the finish with a thin coat of spray lacquer as per instructions on the spray can.