Internet Explorer

Windows XP
Tools > Internet Options > under Temporary Internet Files, click on "Delete Cookies" and "Delete Files".

Mac
1. Open Internet Explorer.
2. Click on the Explorer menu.
3. Click on Advanced within "Web Browser".
4. Click on "Empty Now".
5. Scroll down to Cookies within "Receiving Files".
6. Hold the Apple key and click on each file so that all files are selected.
7. Click on the Delete button.