A mold for shaping glass can be made by a method that includes providing a mold body having a shaping surface comprising at least about 90% nickel and modifying the composition of the shaping surface of the mold body by exposing the shaping surface to an oxidizing heat treatment. The oxidizing heat treatment may include a ramping heat treatment, a fixed heat treatment, or both the ramping heat treatment and the fixed heat treatment. The ramping heat treatment may include increasing a heating temperature at a rate from about 20° C./hour to about 500° C./hour to a temperature from about 700° C. to about 1000° C. The fixed heat treatment may include holding the heating temperature from about 700° C. to about 1000° C. for a holding time of at least about 5 minutes.