Since MSIE 5 saves
some pages to your disk cache to speed browsing, you can tell the browser to skip secure pages, such as e-commerce sites where you enter a password, your credit card number, or other sensitive information.
To do so, click Tools, Internet Options. Click the Advanced tab. Scroll down and check the box marked Do Not Save Encrypted Pages To Disk. Click OK to finish.
Note: You can also check the box to empty out your temporary files upon exiting out of IE to give you even greater security.