Those of you who use Microsoft Outlook know about its address auto-completion functionality. You type a few letters into the address field and Outlook presents you with a list of possible completions. The list includes those recipients, to whom you sent e-mails recently. The problems start when an address is no longer relevant, either because the person has got a new one, or you don't write him/her many letters any more.

It would make sense to clean the list from unnecessary names, but I didn't know how to do it. But a colleague of mine has shown me the trick. Essentially, all you do is: select the address to be removed from the drop-down box and press "Delete". That's it! Outlook will respect your wish and will not show the name again in the future.