I have this door family with nested door hardware.
This door hardware family is created by someone else. They have added a bunch of line styles, fill patterns, categories... (probably via "transfer project settings") into this family.
I want to replace this cluttered family with a clean new created file. I can delete the previous nested family, But the line styles, some fill patterns can not be deleted / purged. If I place these door families in a new project I get all these unwanted line styles - categories
Just wanted to post this as a warning, be careful what you nest, it seems it is there to stay.
(See also this post)