Hello,
Only by creating the special category “Sales” and adding products to that category.
I suppose there is no other way because WooCommerce filter widgets do not work out of the WooCommerce archive pages (shop and product categories).
Or look for the third-party filter plugin that will work our of the archive pages with products that displayed by the WooCommerce shortcodes. But ask plugin author this question before buying/installing the plugin.
Regards