While helping my 81-year-old mum clear out unwanted clothes from her wardrobe, we came across three half-used bottles of perfume stashed in their boxes since the 1980s and 1990s, when she stopped using them.

Kept in the dark, the trio were still fresh it is exposure to sunlight and heat that makes perfumes go off. None of the scents was to my taste but, rather than throw them out, we wondered if they might be of use to someone else.

An hour or so searching the internet revealed the existence of a healthy vintage perfume collectables market where enthusiasts are willing to pay good money to get their hands and their noses on old scents that have been discontinued or reformulated. It transpired that my mum’s three bottles could be worth around 80.

To find out more about the market, I contacted self-taught perfumer and vintage scent collector Sarah McCartney. The attraction for many collectors is that the formulas for famous perfumes change over time, often because perfumers have to remove ingredients used in the original formula that have been banned or restricted by the International Fragrance Association (IFRA), the body that regulates the guidelines for safe usage of chemicals and oils in perfumes. So vintage scents often smell very different to their modern versions.

The use of oakmoss, for example, a species of lichen that grows on oak trees and a common ingredient in a lot of classic scents, has been severely restricted in recent years. Other natural materials such as certain musks, once much used by perfumers, are no longer considered safe and have been banned.

“In shops, perfume retailers will often tell you that the formula in a particular scent has been the same for ever, but that is not true,” McCartney says. “The art of the commercial perfumer is to make scents smell as close as possible to the original. Perfumes are also sometimes reformulated to follow fashion trends or to reduce costs by using cheaper versions of an expensive ingredient. So my interest in smelling vintage and discontinued perfumes is to compare the old with the new.”

The term vintage is quite loosely defined in the perfume world. If, hidden at the back of a cupboard, you have Shocking by Italian fashion designer Elsa Schiaparelli, in its original 1930s mannequin-shaped bottle, then congratulations it is worth up to 1,000. Bottles of Chanel No 5 from periods such as the 1950s are also highly prized. However, collectors will be interested in any pre-2000 recognisable brands because it was around this time that a number of EU restrictions came in, causing many perfumes to be discontinued or reformulated.

“So if you have some old perfumes from as recent as the 1980s and 1990s, don’t chuck them out,” McCartney says. “If you are not interested in starting a collection yourself, you can make money out of them.”

Guardian News and Media 2013