A couple in the UK have just entered negotiations with potential buyers after chancing on one of the grossest (and most valuable) natural resources in the world - ambergris, also known as whale vomit.

A key ingredient in high-end fragrances, thanks to its uncanny ability to make scents last longer, whale vomit hunks can fetch a hefty price due to their rarity - you can't exactly 'predict' where the hacked-up contents of a whale are going to end up. This 1.57-kg lump is estimated to be worth up to US$70,000 (AU$100,000), according to past whale vomit sales.

So first thing's first, how do you find a potentially life-changing lump of congealed whale puke? According to the couple behind the discovery, Gary and Angela Williams from Lancashire in northwest England, you pretty much have to follow your nose.

"It was down a section of the beach where no one really walks," Gary Williams told The Mirror. "It smells too bad, though. It's a very distinctive smell, like a cross between squid and farmyard manure."

As Johnna Rizzo explains over at National Geographic, no one really knows for sure the exact origins of ambergris, but it's thought to be secreted in the bile duct and intestines of sperm whales to ease stomach or throat irritants, such as a spiky squid beak. 

The waxy substance likely greases up anything stuck inside a whale's digestive system, which allows it to be vomited back out. Exactly where it gets vomited out is anyone's guess, but researchers are increasingly looking into the possibility that it comes out the back end, not the front.

"It was once thought the ambergris was ejected by mouth. As of now, the argument seems to be weighted toward the back end of the whale," says Rizzo.

The UK pair reportedly knew what ambergris is, and figured their discovery had a certain 'whale vomit' look about it, so they wrapped it up in a scarf and trundled it home. "It feels like a rock hard rubber ball. Its texture is like wax, like a candle. When you touch it you get wax sticking to your fingers," Williams said. 

Frances Perraudin from The Guardian reports that the couple have already been contacted by potential buyers in France and New Zealand, who might be willing to pay a similar rate that a 2.7-kg lump of ambergris fetched back in 2013 - a cool US$170,00 (AUD220,000). 

A more modest price of US$15,500 (AUD$20,200) was attached to a 1.1-kg piece of ambergris last year.

According to National Geographic, it's illegal to use ambergris to produce perfumes in the US, due to sperm whales being endangered, but it's still a big thing in France - Lanvin and Chanel famously use the substance to make their fragrances last longer on the skin. 

Whatever happens, we hope the Williams won't be disappointed with the price they end up getting for their lucky find, because it sounds like that kind of money really will change their lives. 

"If it is worth a lot of money, it will go a long way towards buying us a static caravan," Gary Williams told The Mirror. "It would be a dream come true."

We thank you for your gift, mystery whale. We hope your digestive system feels better.