Remove certain items from shipping calculations

free-item-shipping.php

function remove_free_shipping_items( $packages ) {
		
	foreach( $packages as $i => $package ){

		foreach ( $package['contents'] as $key => $item ) {
				
			if ( $item['data']->get_shipping_class() == 'free' ) {

				unset( $packages[$i]['contents'][$key] );
				add_filter( 'woocommerce_cart_needs_shipping', '__return_true' );
				 
			} 

		}

	}
		
	return $packages;
}
add_filter( 'woocommerce_cart_shipping_packages', 'remove_free_shipping_items' );