In the overview screen of a Test cycle you can delete products. Select in the 'tree' the product you want to delete and click in the right frame on the Delete function button. Then confirm the deletion of the product in the pop-up.
When you delete a product all underlying products and the linked requirements removed.
If test cases and/or defects are attached to a product then they will be disconnected when the product is removed.
Deleting products is not possible in the list of products The reason for this is that in the list screen you cannot see very well whether there are underlying products and/or requirements that are also deleted. In the tree you have a better view on this.