HTML Cleaner
This tool comes from w3.org and is called 'Tidy Online'.
Just type in your url, and the program will return your 'tidy' html page in a new window. Save the web page to your disk and replace it with your current one.
Alternative to this service you may want to download a free html editor with built in 'HTML tidy': LoGraf Free Website Editor.
This HTML tool provides full syntax highlighting for HTML, CSS, JavaScript and ASP. It also includes a spell checker, an FTP client, link checker, thesaurus, HTML Tidy integration, right-click tag editing, JavaScript`s, RTF import, stylesheet assistant and a table assistant with CSV import.