Be very careful deleting stuff from a Sitecore Analytics database before you hand it over to your hosting company.
The usual approach is to clear the Page, PageEvent and Session tables because these will be full - many months worth of team dev, in my case - of locally registered page views.
BUT - Don't get overzealous and delete the contents of the IPOwner table.
Sitecore Analytics refused to do anything when I did this. Required inspection of the logs, which revealed a problem with some record not actually existing in IPOwner, even though a cursory inspection showed that this logged unique IP's for a session.
Delete these with extreme caution... because analytics stops working, period !