public function execute(\Magento\Framework\Event\Observer $observer)
    {
        /** define local working data */
        /** @var \Magento\Catalog\Model\Product $product */
        $product = $observer->getData(self::DATA_PRODUCT);

        /** perform processing */
        if ($product instanceof \Magento\Catalog\Model\Product) {
            $product->setSpecialPrice(null);
        }
    }