The flame test is used to visually determine the identity of an unknown metal of an ionic salt based on the characteristic color the salt turns the flame of a bunsen burner.
How is the test performed?
First, you need a clean wire loop! Platinum or nickel-chromium loops are most common. They may be cleaned by dipping in hydrochloric or nitric acid, followed by rinsing with distilled or deionized water. Test the cleanliness of the loop by inserting it into a bunsen burner flame. If a burst of color is produced, the loop was not sufficiently clean. Ideally, a separate loop is used for each sample to be tested, but a loop may be carefully cleaned between tests.