""To save a Web page on your computer
On the File menu, click Save As.
Double-click the folder you want to save the page in.
In the File name box, type a name for the page.
In the Save as type box, select a file type.
Do one of the following:
To save all of the files needed to display this page, including graphics, frames, and style sheets, click Web Page, complete. This option saves each file in its original format.
To save all of the information needed to display this page in a single MIME-encoded file, click Web Archive. This option saves a snapshot of the current Web page. This option is available only if you have installed Outlook Express 5 or later.
To save just the current HTML page, click Web Page, HTML only. This option saves the information on the Web page, but it does not save the graphics, sounds, or other files.
To save just the text from the current Web page, click Text Only. This option saves the information on the Web page in straight text format.
With Web Page, complete and Web Archive, you can view all of the Web page offline, without adding the page to your Favorites list and marking it for offline viewing.
When you choose Web Page, complete, only the current page is saved. If you want to view Web pages and the pages they link to while offline, click Related Topics below. ""
So offline content really is only web pages saved to your computer so you can read then later. Where they are saved to depends on where you have chosen. I must admit I am not sure how IE would be able to delete offline content, especially if you saved the pages to one location, then moved them elsewhere later.
Running: XP(SP2), IE6
In Internet Options, General tab, Temporary Internet Files section, hit the Delete Files button. In the resulting Delete Files box, the option is given to "delete all your offline content stored locally." Please tell me how to locate this "offline content stored locally," so I can take a look at it and make the decision whether to delete or not delete.