Scrap towns are settlement built out of the ruins of civilization, made out of scavenged materials, usually plates of metal and wooden planks. More advanced scrap towns have been known to also use brick and plaster, such as Cliffguard.
After the Flash, scrap towns became the dominant place of habitation for most of the U.S.' population. As time progressed and infrastructure was repaired, regular cities started to bring in more people than the small scrap settlements.
Prominent examples of Scrap Towns in After the Flash are Cliffguard, Craterview and Crane Town.