Clean and maintain tile flooring

Unfortunately, we do not know what kind of tiles these are.

You can ask the owners what it is and how they cleaned it. I assume it is natural stone slate. So use a common cleaner for natural stone.

You can ask the owners what it is and how they cleaned it. I assume it is natural stone slate. So use common cleaner for natural stone.

I agree. Looks like slate (or similar stone).

I also thought of stone. If it is slate: Do not use acidic or alkaline cleaning agents. Water is key. Avoid waterlogging. Sometimes you can remove old stains with a poultice. Once stains have set, you can consider it as patina or contact a stone restorer.