Change Archive in Database

I had to go into the log_visit table to change some of the site_ids on visits going back a few days to make up for an error in site_ids when we set up a new site (we used the same id by accident). The problem now is that the archive_blob_02/03 and archive_numeric_02/03 tables have incorrect information. How can I force piwik to re-archive this data? If I simply remove the tables, will piwik regenerate them or will this cause problems? What is the best way to force piwik to rebuild this archive data?


I must have missed it in the FAQ.

Much appreciated!