In August of 1950, Modern Mechanix magazine ran an article called "I Shampoo the Sidewalks of New York," written by ex-sweater manufacturer Louis Schwartz, who ran the Sidewalk Sanitation Service (S.S.S.). He launched the service in 1949, with just one NYC department store manager letting him restore his sidewalks to a sparkling state (he claimed his "scientific, mechanized methods" would "restore beauty" to the pavement). By the time he wrote the article, he had many of New York’s leading stores and hotels on board, stretching over 40 city blocks; he was also The New Yorker's Talk of the Town in 1953.
He began his project by creating the perfect cleaning solution; he writes, "Every night for a couple of weeks I stationed myself in front of Bergdorf Goodman, poured on the detergent, then scrubbed away with a brush. After scouring for a while and noting the effect on the pavement, I’d go home."
Eventually he moved on to help design the scrubbing machines (which he says were based off of the city's own street cleaning machines at the time; they were first introduced in 1855), and eventually he got permission from the city to use them. In the end he started up his business for a grand total of about $15K, and received accolades from locals—including one woman who told him "she would personally go and speak to the mayor and ask him to duplicate our service on all the streets of New York."
So what came of Schwartz? He was the Talk of the Town again in 1962, when The New Yorker reported on one of his new inventions, noting that he sold his cleaning business in 1957, picked up a BS degree from Columbia, and was working towards a Master's degree in political sociology.