To delete products from your Catalog, follow these steps:
Go to: left menu button > Catalog
Click on the checkbox on the products you wish to delete.
Then click on the "More" button found on the top right.
You will then see a "Archive" option, click this and the products will be archived from your Product Catalog.
Once you filter it to Archive, you are then able to select the item you had moved into Archive and click the delete button that is at the top right hand corner of the page.
To delete through the archive files, is an extra precaution to ensure product isn't permanently deleted and you are able to restore the item if necessary.