The dead wax (also called the run-out groove or trail-off area) is the smooth, ungrooved space between a vinyl record's last track and the center label. While it appears blank to the naked eye, this area contains important information hand-etched or machine-stamped into the vinyl: matrix numbers, catalog codes, mastering engineer initials, and pressing plant identifiers.
Matrix numbers in the dead wax are the primary tool for identifying specific pressings of a record. They reveal which master lacquer was used, which stamper pressed the disc, and often which pressing plant manufactured it. On Discogs, matrix numbers are the key data point for distinguishing between first pressings, reissues, and different country editions. Learning to read dead wax is an essential collector skill.
Beyond the technical data, dead wax is also home to one of vinyl's most charming traditions: secret messages. Mastering engineers often etch personal inscriptions, jokes, or cryptic phrases into the run-out groove. Famous examples include George Peckham's "A Porky Prime Cut" on countless UK pressings, and the hidden messages in Led Zeppelin, Smiths, and Radiohead records. Check your records with a flashlight — you might find hidden gems.
Jack White of The White Stripes is known for hiding elaborate messages and even hidden tracks in the dead wax of his vinyl releases on Third Man Records.