If you want to selectively edit the URLs, the ones you've typed in, go to Start>Run and type in regedit and navigate to
HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\TypedURLs
and delete the TypedURLs you dont want. However, the drop down list also relies on your History folder to bring up the URLs. So, just hit Ctrl+H to open the history sidebar, select the entries and sites you dont want and hit delete and then restart the browser and Windows to complete the cleanup.