The Spacelab Headquarters also comes with advanced decommissioning and salvage equipment that may be utilised to regain some resources from unwanted hulls that <player> may wish to repurpose elsewhere, rather than simply selling the hulk. While not wholly efficient, the process can render a hull down to provide useful materials that may be utilised for other projects
Any equipment/wares stored/installed on the ship will be destroyed & not figure into the recycling calculation, so strip the hull completely before scrapping!
A 100% hull will yield ~80% of its build material resources (except for some special additions); the yield decreases proportionally with hull integrity
As with Reverse Engineering, a large or complex hull may take some time to scrap. In the meantime its docking port won't be available for (eg) traders, so manage your queue of scrap ships appropriately if you wish to retain a constant flow of materials for other tasks