How do I clear Cart purchases from the cart

Since there is no delete button for item in the Zoom shopping cart, the way to completely empy cart and to remove top right icon of the cart is to remove Zoom cookies from your browser (even if you are not logged in your Zoom account). After that, you need to close your browser before it takes effect. Next time you visit https://zoom.us , the cart icon with items should have disappeared. But if you shop and buy a Zoom product, the cookie will be recreated and the cart containing an item will reappear.
Note that if you open zoom.us with another browser, you won't see the cart containing an item, unless you also used this browser to shop for Zoom product and it may show a different item because the cookie is different in this browser.