They use the ambergis after it has been refined and liquified
From Wiki:
Freshly produced ambergris has a marine, fecal odor. However, as it ages, it acquires a sweet, earthy scent commonly likened to the fragrance of rubbing alcohol without the vaporous chemical astringency.[2] The principal historical use of ambergris was as a fixative in perfumery, though it has now been largely displaced by synthetics.
That's a pretty well-known fact. Still, it makes me wonder who discovered noxious whale puke's beneficial uses and how.