nail clippers, cat nail clippers...providing rough surfaces in the cage to help wear down claws, (not so good on the back legs...still always have to trim those on mine).

If using clippers be careful to avoid cutting into the 'quick' which is the living part of the nail, full of blood vessels and nerves. You can see it as a darker area in the nail from the side...or limit cuts to just the tip or before the middle point of the nail curve.
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PHLdyPayne