Completely removing old version of MS Office

Question

I have been migrating my account from Mac to Mac for years now. Every time a new Office version is out, I'd install it (X, 2004, 2008, and now 2011) and remove the old one after some time.

Every time, I removed the older version by trashing its folder in /Applications. Now, I get worried that I left tons of support files and stuff in various Library folders. The reason I realized that is that, this morning, Office offered me to update “Open XML File Format Converter”, which I think is now a remnant of the past (and is not part of Office 2011 any more).

So, how can I remove old Office support files and directories, without hurting my current install of Office 2011? Where should I look?