Fabric softeners’ popularity has been declining for years, the Wall Street Journal reports. U.S. liquid softener sales fell 15% overall between 2007 and 2015, and sales of Procter & Gamble’s leading Downy brand dropped 26% in the same period.

Bibie Wu, vice president of fabric conditioning for Germany’s Henkel AG, which acquired the maker of Snuggle fabric softener, says millennials are “eco-conscious” and don’t want to use too many chemical products in their home.

But Shailesh Jejurikar, P&G’s (PG) head of global fabric care, has a simpler explanation. Most millennials, he says, “don’t know what the product is for.”

Fabric softener became popular in the 1960s because laundry came out of the washer feeling rough and scratchy, according to the Journal. But innovations in detergents and washing machines have lessened harshness and therefore need for additives.

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