save as cache drop down list- how do I delete it?

Use CCleaner to clear the MRU ( most reciently Used lists )

and to clear the drop down search box in online searches ( you need to disable Autocomplete, in Netscape this is located iirc in Preferences > Navigator > Smart Browsing > and untick Location Bar AutoComplete or you can goto Advanced and look over the list of sites you have visited and delete as necassary.


Edit:

To manually remove the Save As references from the registry you will have to check these locations.

Office ( subsitute the XXX for the version of Office )
Software\Microsoft\Office\XXX\Common\Open Find\Microsoft Word\Settings\Save As\File Name MRU
Software\Microsoft\Office\XXX\Common\Open Find\Microsoft Excel\Settings\Save As\File Name MRU
Software\Microsoft\Office\XXX\Common\Open Find\Microsoft FrontPage\Settings\Save As\File Name MRU
Software\Microsoft\Office\XXX\Common\Open Find\Microsoft PowerPoint\Settings\Save As\File Name MRU

System or Common Dialog
Software\Microsoft\Windows\CurrentVersion\Explorer\ComDlg32\OpenSaveMRU
Software\Microsoft\Windows\CurrentVersion\Explorer\RecentDocs
Software\Microsoft\Windows\CurrentVersion\Explorer\RunMRU