Sometimes (when Koko”s feeling lucky) Penny does Koko”s nails for her, but other times (like in this photo using her nail file) Koko takes the initiative.
You can view a cute little (Quicktime) video clip showing Koko getting a manicure by Penny on KokoTV; it”s called Nails, Nails, Nails! (Please come back and help Koko save her species when you’re done watching. Thanks.)