Titanium is a very strong, durable metal. Over time, your unpolished Titanium pendant will become naturally polished by your skin. Although this metal is very durable and hard to damage, it is not completely scratch resistant.
If your Titanium piece becomes dirty, you can clean it by letting it soak in warm water and mild soap for several minutes.
If your titanium jewellery is not very dirty, you can just polish it using a polishing cloth, which you can buy at any jewellery store.
To clean your chains, soak in warm water with mild soap. After several minutes, dry with a soft cloth (preferably 100% cotton or microfibre).