Salvaging has changed in version 0.0.7 and it seems to be throwing a few players off who played the last version, so I thought I'd clarify the changes slightly.
Ruins no longer contain all types of loot. You won't ever get rubble out of a car. Or wood out of a light post for example. Or scrap metal out of a utility post.
But (for now) your scavengers still go for the closest ruin no matter what you're lacking. We will change that, but for now, you can make your life a lot easier by experimenting and seeing what each ruin contains in abundance and focus your manual salvages as the town leader on ruins that give what you need.
Another tip: Did you know ruins are FREE to convert into storehouses if you leave most of the loot in them? Is your storehouse full? Do you lack the resources to build a new one... That ruin over there might solve your problem.
Hope that helps those who were lacking [resource X]!
I do like the improvement so you aren't inundated with loot and makes it a little more challenging in the beginning to get your base started. I have tons of scrap metal and rubble but wood I have to direct my leader to gather wood from certain buildings. Being able to set priorities for resources in the scavenge mode would be an awesome addition in the long run. Great update so far and haven't ran into any problems.