Remove/Hide Woocommerce Added to Cart Message but Keep/Display Coupon Applied Message

this worked for me:

add_filter( 'wc_add_to_cart_message', 'remove_add_to_cart_message' );

function remove_add_to_cart_message() {
    return;
}

Update: 18/05/2018 Please refer to bellmountain's much simpler answer for the correct way to do this.

Add this code to your themes functions.php file. It will remove only that message. It should trigger on just the pages where it is likely to occur.

function remove_added_to_cart_notice()
{
    $notices = WC()->session->get('wc_notices', array());

    foreach( $notices['success'] as $key => &$notice){
        if( strpos( $notice, 'has been added' ) !== false){
            $added_to_cart_key = $key;
            break;
        }
    }
    unset( $notices['success'][$added_to_cart_key] );

    WC()->session->set('wc_notices', $notices);
}
add_action('woocommerce_before_single_product','remove_added_to_cart_notice',1);
add_action('woocommerce_shortcode_before_product_cat_loop','remove_added_to_cart_notice',1);
add_action('woocommerce_before_shop_loop','remove_added_to_cart_notice',1);

Don't worry about using that css you've tried.

I`m using this:

add_filter( 'wc_add_to_cart_message_html', '__return_null' );