The English expression ‘museum piece’ has two meanings. Its overt and straightforward meaning is that of an object that is, or that deserves to be, preserved and made available to an audience for their edification and delight.
The other meaning is ironic – that the object is no longer of any use, and that it is old-fashioned, dysfunctional, and needs to be disposed of. What is interesting about the phrase is that in both senses – the overt and ironic – it emphasises the non-utility of the object: in the straightforward sense, it is something to be removed from the everyday and placed in the care of an institution whose task it is to preserve it for posterity; and in the ironic sense, it is to be discarded. This expresses the special nature of objects in museums: that they leave the functional everyday environment of use and are placed in a special environment where they serve an entirely different purpose, are treated in a very different way, and are consequently thought about and understood in a new way. The process is one of removal from the mundane world, in which things decay, to a special realm where things exist in perpetuity.