The Colonial Cities are a collective of incorporated cityscapes that play host to comers-and-goers from the OSK, informally playing liason between those who live above the clouds and those who toil in the refuse. There is no clear legal boundary between the Scrapyards and the Colonial Cities on most days, at least not beyond the vagueries of what identification is valid, how high the bribes run, and just how polished the boots that stamp your head in happen to be.
When everything is dirty -- "even things that just orbit us get covered in ancient astronaut shit," as an Old Man once remarked -- it's just a matter of how clean you can afford to be.