Servicing a lens typically involves cleaning and maintenance to ensure that it functions properly and produces clear and sharp images. Here are the steps involved in servicing a lens:

1. Clean the lens: Use a soft, lint-free cloth to gently clean the front and rear lens elements. Be careful not to scratch the surface of the lens or use any harsh cleaning agents that could damage the lens coatings.
2. Check for dust and debris: Use a small flashlight to check for any dust or debris that may have accumulated inside the lens barrel. If you see any, use a soft brush or blower to remove it.
3. Lubricate moving parts: If you notice any squeaking or grinding sounds when you adjust the focus or zoom, you may need to lubricate the lens's moving parts. Use a small amount of camera lens lubricant and apply it to the appropriate areas, being careful not to over-apply or get any lubricant on the lens elements.
4. Check the aperture blades: Inspect the aperture blades to make sure they're clean and free of oil or debris. If they're dirty, use a clean cloth or brush to gently remove any dirt or debris.
5. Test the lens: Mount the lens on your camera and take some test shots to make sure it's functioning properly. Check for sharpness, focus accuracy, and any other issues that may affect the image quality.

If you're not comfortable servicing a lens yourself, it's always a good idea to take it to a professional camera repair service. They will have the tools and expertise necessary to service the lens properly and ensure that it's working at its best.