How can a "clean slate" sync be done between N900 and Outlook?

Namely, I also tested Nokia PC Suite (in addition to previous Nokia Suite sync), which made quiet a mess with some contacts and appointments (duplicates or near-duplicates). I managed to clean the situation in Outlook, and I don't want to go through this time-consuming experience again. Is there a way to reset sync status somehow (I guess if I just delete everything in N900, the next sync will delete everything in Outlook. And I know now that I should never mix Nokia Suite and Nokia PC Suite again...)?

Maybe I should look into other one-way options, such as exporting to a file in Outlook, and importing in N900.