Deleting items on an individual basis
If you have just a few items, you can visit your "Selling > Add or edit items" page and click the "More" link on the tool bar above the item you want to delete, then click the "Delete Listing" link from the menu that appears.
Deleting items in bulk
If you've got a lot of items you want to delete at once, you can use the batch editor to do this by going to the "Selling > Batch edit items" page. You can select multiple rows of items. Select the "delete" option in the tool box at the top of the page, then click the "Apply changes" button and all selected items will be deleted. See also Batch Edit Items for more information.