A device used to quickly and efficiently delete any signals stored on a compact cassette, including sound and sonically encoded computer-readable information. Its working principle is based on the influence of a strong magnet, placed inside the device on the magnetic tape of the cassette, that overrides the previously existing magnetization caused by the recording head. Similar erasing devices also exist for other formats. Although standard cassette recorders could delete an existing recording, the procedure was slow because the tape had to be moved past the deleting head, and the results depended on the correct alignment of the apparatus. The practice of using the recording medium repeatedly, and thus the need to delete information, did not emerge only with the advent of the compact cassette or even the magnetic recording principle: in the Edison phonograph, the audio stored on the wax cylinder could be erased by scraping away the outer layer of the recording surface. In a physical format such as the phonograph cylinder, repeated deleting can lead to the destruction of the recording medium, but the magnetic tape does not suffer from erasure in the same way.