An autoclavable cassette for the receipt and storage of dental and surgical instruments includes a metal tray portion including a base, four sides and two outwardly extending flanges and a metal lid portion which covers the open tray portion and assembles to the outwardly extending latches by means of a cooperating latch and pin combination. The metal cassette tray is configured with a variety of slots, apertures and pins which are used to receive customizing components so that the dentist or surgeon can, by his own selection of specific component options create his own customized cassette. Some of the customizing options include a generally rectangular rack which sets in and can be lifted out of the tray and which includes a series of aligned receiving channels for the receipt of dental or surgical instruments. Another customizing option includes a finger mat which fits within the tray with a snap-in/snap-out feature, providing greater versatility. A third customizing option is a metal storage box which can assume a variety of configurations and is used for smaller or irregularly shaped parts. In one variation of the preferred embodiment, two storage racks can be used in a stacked configuration so as to increase the capacity of the dental cassette.