Comment by viraptor

The "less cleaning due to less coal" part is not something we really think much about these days, but the older limestone buildings can really show the difference. Here's a view with the old and either pressure-washed or redone wall: https://maps.app.goo.gl/Wso9gae4JPsN6NaG6 and that's on a residential side street... Imagine getting your clothes slowly covered with it every time you go out.