skEdit includes integrated support for HTML Tidy to provide HTML cleaning and conversion. While skEdit ships with several pre-built Tidy operations, it is also possible to construct your own operations to meet your needs. Tidy operations can be run on a single file or multiple files simultaneously.
To quickly run a Tidy operation on the current file, you can use the "Tidy Markup Cleaning" item in the HTML menu. It will provide access to all defined operations. These operations are non-destructive - you can undo/redo them just like any other text modification.