underblob

Here’s how to remove all instances of all plugins from an element if the plugin does not include a destroy method:

$.removeData($element.get(0));

This will not remove the bound events. You have to do that separately.
If the plugin you’re trying to remove has namespaced events, you’re in luck:

// Remove namespaced events added using .on()
$element.off('pluginNamespace');
// Remove namespaced events added using .bind()
$element.unbind('.pluginNamespace');

If not, you can examine all of the events attached to an element:

console.log(
	'$element events:', 
	$._data($element.get(0), 'events')
);

Here’s all wrapped up in a handy function:

var destroyCrappyPlugin = function($elem, eventNamespace) {
	var isInstantiated 	= !! $.data($elem.get(0));

	if (isInstantiated) {
		$.removeData($elem.get(0));
		$elem.off(eventNamespace);
		$elem.unbind('.' + eventNamespace);
	}
};