A junk dealer, also synonymously known as a refuse merchant, scrap-metal merchant, or scrap peddler, was someone who sold junk, scrap, and other items, often salvaged from abandoned starships.
When commenting on his brother Rom's messy quarters while living with him for a time in 2371, Quark told him to clean them up, because he wasn't going to "tolerate living like some Pakled refuse merchant", in addition to all his brother's other quirks. (DS9: "Prophet Motive")
In 2372, Razka Karn bought a piece of uridium alloy from a Ferengi scrap-metal merchant that appeared to be a forward sensor array from the missing Cardassian ship Ravinok. (DS9: "Indiscretion")
Abaddon was the owner of Abaddon's Repository of Lost Treasures. (VOY: "Alice")