To delete (move to trash), just select the products you want to delete, click the Delete rows button and say yes in the dialog. Here is an example:
Just find the products you want to delete. (products will be moved to trash so you are able to get them back if you did something wrong).
Check the items you want to delete (or use the check all – left to Name in the header), then click Delete rows (button) and say OK in the dialog and your selected products are deleted.