It would require introducing ruins or archeology hot areas to map.
Junk piles will be gone. Someone needs to get us old technology, like blueprints of old and old weapons and tools. Wandering around a field or forest and then scavenging just to find a blueprint how to make certain armor part is highly unlikely. Archeologist would have a certain set of tool to work with (hammer, chisel, brush, spatula?) and would be main source of old knowledge.
Ruins would also be good magnet for pvp action, tribes would have to go in and secure them so their archeologist wuold not be ganked. Also stronger tribes would stop moaning about people being in safe zones and could use their strenght to dominate sources of blueprints.
Ruins should not be nowhere near tribal areas and no one should be able to settle over a ruin and claim it by totem.
Maybe archeology could be specialization line of scavenging?
scavenging is really the archeologist of the game. What I would do along this line of thinking is to have ruins where scavenging is likely to find items from the lost civilization. This would be a separate item set than what you could scavenge in the normal areas.