As units of plant and equipment wear out or become obsolete, they must be scrapped, sold, or traded in on new equipment. Upon the disposal or retirement of a depreciable asset, the cost of the property is removed from the asset account, and the accumulated depreciation is removes from the related contra-asset account. Assume, for example, that office equipment purchased 10 years ago at a cost of $20,000 has been fully depreciated and is no longer useful. The entry to record the scrapping of the worthless equipment is as follows