Koko tries on a pair of sunglasses and knows she looks good in them. However, Penny refers to them as "little alien glasses" which Koko seems to find insulting, as indicated by her final comment (in sign language). Note also that Koko attempts to clean her glasses by first "huffing" on them to create some moisture, and then rubbing them with her finger. Penny then offers to bring her a kleenex to complete the job. Another thing to note is that Koko is actually signing "glass" when she taps on the glasses with her fingers.