Scavenging
This is an action that you can take alone or with Followers in any map area, and it is also a Job that you can assign followers to do on their own.
If doing it yourself with or without Followers, each Scavenge attempt will take an hour (take the Investigate Area -> Scavenge Area action), and will succeed or fail depending on your own Survival skill. You will have a reduced chance to find something in Safe areas, whereas in Wild areas there is a chance you'll attract an attack from a rival scavenger gang (which is the main reason it's worth having your Followers accompany you on Scavenge actions). If your scavenge attempt is successful, you will find mostly Merchandise and scrap metal, with smaller chances for things like fasteners and cloth, plus a smaller-still chance of finding something unusual e.g. a shotgun (maybe "finding" things like this is why you get attacked sometimes?)
If assigning personnel to the Scavenger job, they will do this 9am-5pm; it is theoretically risky, though in practice so far has turned out to be safe; and they will bring back a guaranteed haul unlike a Scavenge action, and their haul will be greater - but that's because a Scavenge action takes only for an hour. They will bring back less if their Survival skill is 20 or lower, and more if it's 60+. They will also bring back extra if they are smart (Intelligence 60+), like you (Affection 60+), Ikaanos is thriving (Prosperity 75+), or if they have the Scavenger trait. However they will bring back only Merchandise, unless they have the Scavenger trait, in which case there's a chance for Durasteel, tendstims and energy cells.