Harold got some of the alchemic chemicals in the tub and it gave Harold's skin a gold-dusty sheen. Even against the gold watch, his skin seems to shimmer. This was an accidental discovery that will probably be the first of many applications. This one might be cosmetically enhancing. Even without revealing his techniques, Harold could supply for instance an homeopathic ingredient (like white gold) to a pharmaceutical supply or in this case, to a cosmetic company.
Again this discovery was an accident. Harold had chemicals on himself and was washing them off in the tub. After he got out he noticed that his skin glowed with a gold-dusty sheen.