Best way to delete all list items from a child site

I need to delete all list items in a child site from the parent site. The list is very small less than 20 items.

Need your suggestion on the best way to do it.

1.  Delete this list and re-create a new one?

2.  Use nintex 'delete multiple items' action. This action requires the list id i need to get dynamically

3. Call the sharepoint web service lists.asmx. I didn't find a method to delete all items.

Thanks