Delete one or more nodes, cables, and/or comments from your canvas by selecting them and either pressing ⌫ or right-clicking one of your selections and selecting from its context menu.
When you delete a node, any cables connected to that node are also deleted. A cable with a yank zone may also be deleted by yanking it from its connected input port and releasing it.
Any type converters that were helping to bridge non-identical port types are automatically deleted when their incoming cables are deleted.