fun fact: you can have chimney grime on your face without wearing blackface
One of the towns near me, where I used to go to school, has a Victorian Week every year where the people and schools all dress up in Victorian costumes of varying social classes, and they celebrate the towns Victorian heritage (it's an old Victorian seaside resort town).
There's commonly men and boys with grimy faces dressed as chimneysweeps or steam train conductors.
There's no accusations of anything close to blackface.