When you delete an item, it is kept on the products database as deleted items. So if you do not want them anymore on the database, you should do this at the web version. That is at
Database > Products > View / Edit > Settings
Select Delete items > Save
On the screen you will see the items that have been deleted. Now you may select one by one or select all to erase them
One by one Select the icon > basket
All of them Select icon > basket
once it is done you should click on settings to unselect the option Delete items > Save