Passengers said on social media that when they boarded a subway car on Saturday night they found someone had drawn messages in black marker targeting Jews and Muslims and praising Adolf Hitler, the German leader responsible for the Holocaust.
"The train was silent as everyone stared at each other, uncomfortable and unsure what to do," attorney Gregory Locke wrote later in a Facebook post.
Then, he added, "One guy got up and said, 'Hand sanitizer gets rid of Sharpie. We need alcohol.' He found some tissues and got to work."
The Nazi symbolism was gone within two minutes, he added.
Locke's Facebook post had been shared more than 354,000 times as of Sunday afternoon.
The cleanup was not a planned event but an example of spontaneous unity in a metropolis that prides itself on diversity, passengers said.
Those who joined the effort were "satisfied in just doing the right thing," another of them, chef Jared Nied, told CNN.
The number of hate and bias incidents reported across the United States jumped in the days immediately after President Donald Trump's election victory in November.
Early Saturday morning, the large front window of the Chicago Loop Synagogue was smashed and swastika stickers affixed to the building's front doors.
Illinois Governor Bruce Rauner condemned the attack in a statement on Sunday. The Chicago Police Department described the suspect as a white male wearing dark clothing and a dark mask.
The subway incident was reported on Sunday to the New York Police Department, which is investigating it as a possible hate crime, Sergeant Jessica McRorie said.
The cleanup happened on a subway train near the Lincoln Center arts complex on Manhattan's Upper West Side, McRorie said.
New York Governor Andrew Cuomo said on Sunday a similar incident happened in recent days, when a passenger on a different train spotted a swastika scrawled over an image of an American flag. The passenger, whom Cuomo did not name, used a marker to turn the symbol into a box with four quadrants and wrote in the letters L-O-V-E.
"This is what New Yorkers do - we turn hate into love," Cuomo wrote on Twitter.
Banner Image Credit: Reuters