Reminds me of my first year at university doing Chemistry
You could always tell the male Chemistry students as they washed they hands before going to the loo - at least during the day
and we all had yellow stains on out fingers and often node as well
the reasons was that one of the techniquies we had to master used Turmeric
and we had to seperate out the yellow pigment from the rest of the spice
we all know how much turmeric can stain - so imaging what the pure colour chemical does!!!!
and clearly your nose itched
hence washing hands - you really didn't want to have to answer question about yellow stains "down there" - well we all hoped to be in a position where we might get awkward questions anyway!!!!!