It generally gets them very clean! just don't put the wires or PCB in there.. or buy one of those keyboard covers or make them have baby bottles, that'll make them learn.
tonyhughes: Expectations need to be set right with kids from the outset. I never put my guitars etc away from my now 2.5 year old, even when he was a crawler, he was taught to not play around with them, and now he always comes and asks politely if I can play the drums so that he can play the guitar.
Involuntary autocorrect in operation on mobile device. Apologies in advance.