My theory about why they wear white cloves is that the cartoonist can more clearly show expression more clearly in the hands. Black lines can be used to more clearly show the fingers and their positions – all of which enhances the emotional expression of the characters. To put it plainly you can see the hands better if they’re white.
And the dilution factor is…..pretty high, I’d say. Plus you towel off what very little is left on your skin.