Flotsam

You may be looking for the salvage merchant or the short story Flotsam and Jetsam.

Pieces of flotsam and jetsam floated around in outer space, and came through the Cardiff Rift. (TV: Everything Changes, Captain Jack Harkness) Tonnchenforms only ate bits of flotsam and jetsam. (PROSE: Normality)

Flotsam included spaceships (TV: The Infinite Quest, PROSE: Methuselah) and rockets. The Second Doctor told Jamie McCrimmon that in the Silver Carrier, they were "just a piece of space flotsam". (TV: The Wheel in Space)

After the Infinite was destroyed, it became flotsam spread over half the galaxy. (TV: The Infinite Quest)