How do I clean white Plastic?

So I have two white blink-182 guitar picks and I went to see my Dad and Brother in Toronto for 10 days in the beginning of June. My brother is a total **** and actually holds Picks in his mouth and like sucks on them. That seems to have stained my picks. I don't know if the stains are smearing of the paint or dried up Saliva. the picks are clear coated. Please don't tell me to buy new ones because these are rare picks. Thank you to anyone who provides a helpful answer.