I haven't seen an answer posted to this so I thought I'd throw my two cents in.
I've been in this position. Anyway, if you're savvy enough I bet you can do this via your php MyAdmin panel. Either go row by row or write a query. Might get someone on the site here to help write a query.
Hope this might help some.
PS. This thread is in the storefront customization area and probably isn't getting the attention it would in the Technical Support -> Misc. forum above. Maybe ask a moderator to move or repost. ???