Backup First!Before you do anything please backup your WordPress Database using a WordPress backup plugin like BackupBuddy by iThemes.
1. To delete all your WooCommerce Products, for a fresh start, you will need to access the database directly via a database application such as phpMyAdmin (included in many hosting Control Panels). Navigate to your WordPress Database and then in the SQL tab enter the following database query:-
DELETE relations.*, taxes.*, terms.* FROM wp_term_relationships AS relations INNER JOIN wp_term_taxonomy AS taxes ON relations.term_taxonomy_id=taxes.term_taxonomy_id INNER JOIN wp_terms AS terms ON taxes.term_id=terms.term_id WHERE object_id IN (SELECT ID FROM wp_posts WHERE post_type='product'); DELETE FROM wp_postmeta WHERE post_id IN (SELECT ID FROM wp_posts WHERE post_type = 'product'); DELETE FROM wp_posts WHERE post_type = 'product';
2. Click ‘Go’ in phpMyAdmin to run/execute the SQL Query
This will delete all your Woo Commerce products and their associations (including categories/taxonomies/terms info) so please exercise caution when running the Query.