If you've done a test import of records and you want to quickly get Evergreen back to a pristine state, you can create a clean Evergreen database schema by performing the following:
cd ILS/Open-ILS/src/sql/Pg/
Rebuild the database schema:
./build-db.sh [db-hostname> [db-port] [db-name] [db-user] [db-password] [db-version]
This will remove all of your data from the database and restore the default values.