Small sections at a time
Do small sections at a time, wiping the polish all over the surface. Then buff into the metal until the cloth feels smooth to run back and forth over the surface. We find its usually about 10 to 20 seconds for lightly tarnished, dull metals. You will hear the polishes working away on the tarnished surface as you rub it in. When it stops making that noise, the abrasives have broken down and the area should now be nicely polished.
For really badly affected surfaces, repeat the process to get better effect (if needed) as opposed to slathering on too much product all at once.
If you have really soft and flat faced alumimium, apply in one direction, in a gentle side to side motion to avoid leaving light polishing marks in the material.