@oreoocat
To reach one of your custom lists, go to the Watch List page (must be that page) using a desktop browser, and click on the large "Watchlist" heading at the top to reveal a drop-down with a selection of your lists. Choose a list and load it.
You can delete the items on the list by using the checkbox at the top of the page to select all items on the page, and then use the delete button icon at the top of the page.
You can delete an entire list (other than the Watch List) by using the "Delete list" link in the upper right corner of the list page.
