Is there a way to mass-delete variations?

I edited my variations file and imported it back (without changing parent IDs or parent SKUs), but it seemed to add variations on top of the previous ones. Now I have too many variations. Is there a way to delete multiple ones? I did “import” not “merge”. I thought “import” would override the previous file but it didn’t. Is there a way to override the previous file?

http://wordpress.org/plugins/woocommerce-csvimport/