Problem with theme unit test data

I’m going to be showing some people how to test themes soon. In preparation, I imported the theme unit test file into a new WordPress site. I wanted to be sure they would be able to delete those pages and posts when they were done with them, so I deleted the users that came in with the file, and removed everything they owned rather than assigning to another user. That seemed to work.

Then, I wanted to go in and take a practice walk through some themes. I wanted to access the theme unit test data again, so I tried to reimport it. The categories, tags, and users reimport, but I get errors that the posts and pages already exist. I guess they’re in the database but I can’t see them through the WordPress dashboard.

Is it possible to remove that data completely so it can be reimported, or is there some other way of making the posts visible through the WordPress dashboard again?