I use finger nail trimmers designed for human babies--they are very tiny. I just trim the very tips off the nails of my young or small tegus. My adult tegu wears down her own nails. This works for my beardies and uros as well. If you look at the nail, you can see the curve and the thickest part has the vein. Then there is a thin part at the end of the curve. Trim the end of the thin part.