The present invention general related to a reusable mold for making a contact lens comprises a first mold half having a first mold surface in contact with a polymerizable and/or crosslinkable silicone containing lens forming composition and a second mold half having a second mold surface in contact with the lens-forming composition, and the first mold half and the second mold half are configured to receive each other such that a cavity is formed between the first mold surface and the second mold surface. The cavity defines the shape of a contact lens to be molded. The reusable mold has at least one of the mold halves being made from an oxide glass comprising fluorine and/or fluoride. The mold made by oxide glass comprising fluorine and/or fluoride demonstrates improving mold cleanability with water based cleaning process.