CHICAGO — On March 3, 1821, a New York City tailor named Thomas L. Jennings received U.S. patent 3306x for “dry scouring” — his method for pulling grease and dirt out of clothing. 

Born free in 1791, Jennings was 30 when he developed his process, and he’s widely believed to be the first African American to hold a patent in the United States.

That last fact matters more than it might seem at first glance. Before the Civil War, an enslaved person’s inventions were legally the property of their enslaver. Patent rights weren’t extended to enslaved people until 1861. Because Jennings was born free, he could own what he created, and he worked to make the most of it.

The profits from dry scouring funded abolition efforts, charities and legal aid organizations. Jennings used the money to purchase freedom for family members. He went on to found Freedom’s Journal, considered the first Black-owned newspaper in the country, and the Abyssinian Baptist Church in Harlem. Jennings died in 1859.

Nobody knows what Jennings’ actual cleaning process was because his patent was among roughly 10,000 destroyed in an 1836 fire at the U.S. Patent Office. The industry Jennings started survived. The paperwork didn’t.

In 2018, marketing agency BeCreative360 tagged March 3 as National Dry Cleaning Day in Jennings’ honor. Dry cleaners across the country have picked it up since, the company says, and the observance keeps growing.

“This is a day that has tremendous significance to all of us in the drycleaning business,” says Dave Troemel, marketing director and partner at BeCreative360. “The drycleaning industry has given so much to us, to our families and to our communities. It’s our day to reflect and to also acknowledge the man who started it all.”