To clean and maintain the Nadir Knobs, which are crafted from solid brass, it is essential to regularly wipe them with a soft, damp cloth to remove any surface dirt or fingerprints. Avoid using abrasive cleaners or harsh chemicals as these can damage the brass finish. For a deeper clean, you can use a mild soap mixed with water, applying it gently with a cloth and drying thoroughly afterwards. To maintain the luster and prevent tarnishing, you can occasionally apply a thin coat of brass polish, following the manufacturer's instructions carefully. Regular maintenance will ensure that these knobs retain their elegant appearance and functionality for years to come.