The third store of Scrap value are units and structures themselves. Virtually everything will decay into Scrap once killed. For balance reasons, it takes a unit considerable time to decay into Scrap. Currently, there’s a 90 second window where any unit killed becomes a “burning wreck” with 60% HP and Scrap armor type. At the end of that window, whatever HP the unit has remaining is converted into a Scrap field of that Scrap value.
This way, players are encouraged to vie for control of old battlefields until the timer runs up and the Scrap is harvestable. Also, a player who feels they may not be able to control the Scrap when it becomes harvestable can attack the Burning Wrecks to reduce the value (or completely kill off) of the resulting resources. My hope is that fields of burning wreckage become ever-shifting points of interest on the battlefield as players vie for control of these reusable (though diminishing in returns) resources.