Debris in caves

I've had Astroneer for over a year, and I usually bore of the game shortly after getting shuttles. My current game is the longest I've played, and I feel like I've run out of debris on the surface of Sylva, which is the only place I've built a scrapping operation.How do you deal with debris in caves? On the surface, I usually build a mobile shredder, but I can't imagine doing that in the caves because of all the holes and really rough terrain.