Have a "how-to" question? Try www.eHow.com because it is great. My mom introduced me to the site when Snug put a crayon in his pocket and it went through the laundry. I shudder remembering the day.
Anyway, eHow to the rescue again. I smothered those cups in baby oil (I got this bottle when Snug was a baby as a gift...I never have really had a use for it) and then scrubbed and scrubbed and scrubbed. They're going to go in the dishwasher...we'll see how it turns out!