Cleaning and Shaping the Fangs:
Using a dremel tool or small file clean up the edges, file down the back or front of the fangs as needed. Fit the fangs. If they feel loose you can either add a little more acrylic inside and have the person put them on while it's still liquid. Or use Denture grip when wearing them.

Buff them up with the dremel tool. And for a nice shinny look, brush the fangs with clear nail polish. Warning: Wait at least one day after applying the nail polish.