Bette Nesmith Graham didn’t set out to earn millions: she just needed a way to correct her frequent typing mistakes as a secretary at the Texas Bank & Trust in Dallas in the early 1950s. In the process this single mother invented and patented Liquid Paper, a product that transformed the working lives of millions of typists overnight. Her invention’s effectiveness lies in its simplicity. “Like a safety pin or a rubber band,” she said, “we wonder how we ever got along before without it.”

Born Bette Claire McMurray in Dallas on March 23, 1924, she grew up in San Antonio, became a rebellious teenager, and married Warren Nesmith in 1942. The hasty wartime marriage didn’t last, and she found herself after the war struggling to raise her son, Michael, in Dallas.

Needing to make ends meet, Bette tabled her aspirations to become an artist, a dream inspired by her mother, who had taught her to paint. She joined a typing pool, then signed on as the executive secretary of the Texas Bank & Trust. Her poor typing skills on the new electric typewriters made her job challenging. Erasing her mistakes didn’t work well, so she decided to cover them up. “I knew that when artists do any lettering, they never correct by erasing,” she said. “They just paint over the error. So I decided to use what they use. I put some white tempera water-based paint in a bottle, took along my watercolor brush, and used that at the office to correct my typing mistakes.”

That was in 1951. “Because I was correcting my own mistakes, I was quiet about it.” Her boss didn’t seem to mind, but other bank secretaries took notice and eventually asked her for their own supply of the magic fluid. One night in 1956, Bette filled a bottle with the mixture, labeled it “Mistake Out,” and brought it to work next day.

As word spread, a local office supply retailer suggested that Bette market her invention. She filled out a trademark application but at the time couldn’t afford the patent search fee necessary for a patent application. Instead, she sent herself a registered letter outlining her idea, in the belief that it might provide legal cover if she ever needed it.

Concerned that Mistake Out took too long to dry, she also worked on improving her product. “I started out by going to the library and looking up the formula for tempera water-based paint, which I felt was an ideal pigment and solution formula,” she related in a series of interviews conducted by the University of North Texas Oral History Program in 1977. She worked nights and weekends in her kitchen to refine the formula, working through gallons of water-based paint. She called DuPont and other companies, requesting samples of chemicals she believed might help with drying time and absorbency. She wasn’t a chemist, so she “made lots of mistakes,” including setting her kitchen on fire. Her son’s chemistry teacher taught her a few things. A local paint company employee showed her how to grind and mix paint.

By this time she was working for IBM. She wrote to company headquarters. They asked her to further refine the formula. Instead, she decided to market it herself.

Bette made sales calls to office supply stores in Texas. She bought fingernail polish bottles, then hired son Michael and his friends at $1 an hour to fill them in the kitchen. (Michael Nesmith later found more lucrative work as a musician and member of The Monkees pop rock group.) Bette renamed her product Liquid Paper in 1958, the year that the trade magazine Office included Graham’s invention in a list of new products. Some 500 readers wrote her for more information. “As you can see, I could have used Liquid Paper for this letter,” read one error-ridden missive. The young businesswoman found it increasingly difficult to balance her day job with her freelance manufacturing career. “I would work all day as a secretary and sometimes work all night answering the mail and trying to send the samples, and once in a while I’d get an order for 12 bottles,” she recalled. Then one day, preparing a letter for IBM during her day job, she typed in “The Mistake Out Company” at the end. That mistake cost her the job.

Her company continued its slow growth. She received a large order form an atomic laboratory in New York that wanted blue and beige colors to match the paper it used. The lab became a regular customer. Eventually Bette moved her operation from the kitchen into a prefabricated shed in the backyard and bought two machines, one to fill the bottles and another to screw on the bottle tops. In 1962 she married salesman Robert Graham, who helped her with promotion: “We were traveling in a car and kind of going into a city and picking up the phone book and calling office supply people.”

In 1968 Liquid Paper built a new, fully automated plant that could produce approximately a million bottles annually. Four years later the company opened a plant in Canada, and another in Belgium the following year. Bette added a library and an art collection to the Liquid Paper factory for the employees. The statement of policy for her company reads in part: “We are committed to the idea of a dignity and integrity of man, and we rely on this dignity rather than systems to create leadership and accomplish success.”

In 1979 Bette sold Liquid Paper to the Gillette Corporation for $47.5 million. (Newell Rubbermaid purchased the brand from Gillette in 2000.) When Bette Nesmith Graham died at the age of 56 in 1980, she left a substantial fortune, half of it going to her son (who until 2000 received a royalty on each bottle of Liquid Paper sold) and half to the Bette Claire McMurray Foundation and the Gihon Foundation, charitable organizations she founded to increase opportunities for women. Not a bad legacy for a business relying on other people’s mistakes.