Wiertz Leather Optima Wiertz Leather Optima is a modern, water-based care and maintenance cream with a UV filter to help leather retain its original color longer. Optimal care for full aniline and opaque leathers. Not suitable for suede and nubuck leather. Before use, first clean the leather with Wiertz Leather Intens. Wiertz Leather Optima nourishes and keeps the leather soft and supple. It leaves a protective layer that makes dirt and ballpoint pen ink easier to remove. It also gives the leather a well-groomed appearance.