Hello Mrs Dee,
My name is ***** ***** I'd be glad to help with this.
What you have is an example of an Indian temple toy and quite an unusual one as these are rarely seen in the form of a turtle (tortoise) they are usually other animals such as horses or elephants.
They have come to be known as "temple toys" because the wheeled animals can be so reminiscent of the old-fashioned pull toys that were once popular with small children in the West.
However these Indian versions are not toys.
They are for devotional purposes, for offering donations to Vishnu & Shiva and other Hindu deities in times of need, and are found mostly in Central and Southern India, particularly the state of Tamil Nadu at the southernmost tip of the subcontinent.
The tortoise (Kurma) in the Hindu tradition is considered highly auspicious as it's one of the Avatars of Vishnu (he's one of the three main gods of Hindu along with Shiva and Brahma) and in their creation mythology the tortoise carried the mythical Mount Mandara, home of the gods, and the source of the ambrosia of immortality.
Some of these temple toys can be very elaborate like this example of elephants pulling a carriage, but you'll notice they are often ornamented with those rooster-like finials that yours has.
Yours is most likely early 20th century in date, certainly no newer than the 1950s. It's made from cast brass and is carefully hand-engraved.
If you were to sell your tortoise temple toy on-line (on eBay, for instance) and properly described as what it is, it would sell in the range of $70 - $120.
I do hope this helps!
Please let me know if you'd like me to explain or expand on any of the above, I would be glad to.
PS. No need to clean it. In fact most collectors prefer that old patina of tarnished brass and consider it detracts from value once cleaned. R