I've been wondering for some time how to deal with finger prints on the bean (eg. from unpacking and such). I assume (??)the device was cleaned after manufacturing to remove foreign DNA, but really, I suppose one should only handle it with gloves to not leave fingerprints all over it. Didn't think about it when I got it, and it doesn't matter in my case because I don't use it on anybody else, but what do you use to clean the bean?