All bulbs should be cleaned prior to installation! There are oftentimes oils remaining from the manufacturing process that needs to be removed. These oils can cause hot spots on the surface of the glass that can cause bulb failure and in extreme cases the explosion of the bulb glass from overpressure in the bulb itself. The bulbs should not be touched with bare skin due to the oils from your skin causing the same problem. When installing the bulb into the bulb housing, the bulb glass should not touch the housing, if it does you must remove it and clean the bulb again. Use denatured alcohol and a clean cloth for cleaning bulbs.
Auxiliary Lamp Installation
Proper auxiliary lamp aiming is the most important part of an installation. If the lamps are not properly aimed they will not achieve optimum performance and they can be very dangerous. The danger comes from the beam pattern being aimed right into oncoming vehicles thus blinding the driver. Please see aiming instructions. Make sure the auxiliary lamps do not restrict the airflow to the radiator or obstruct the headlights, turn signals, or marker lights. Route wiring away from moving parts and excessive heat.