Alfa Romeo Giulia Owner's Handbook Manual page 166

IMPORTANT
70) Halogen bulbs must be handled holding
the metallic part only. Touching the
transparent part of the bulb with your
fingers may reduce the intensity of the
emitted light and even reduce the lifespan
of the bulb. In the event of accidental
contact, wipe the bulb with a cloth
moistened with alcohol and let the bulb dry.
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