The two are the brains behind the Typo Eradication Advancement League (Teal). In March, it launched an Outreach Mission to correct apostrophes and spelling faux pas. Deck and Herson travelled nearly 12,000 miles in 73 days, and identified 423 instances of signage marred by mistakes in spelling, punctuation and grammar. They made 231 corrections.
A star of local spelling bees as a child, Mr Deck set up Teal after attending his five-year reunion at Dartmouth College. He said: "I was speaking with some of my classmates who were becoming doctors and lawyers, and other people who could have an impact on the world and I started to wonder how I might be able to do that... fixing typos was what I came up with... I've always been aware of typos wherever I go [and] I figured that it was a national problem".
Soon Mr Deck had founded Teal, complete with a website, blog and a typo correction kit. The tour began on 5 March from Mr Deck's town of Somerville, Massachusetts, and led the pair through more than 20 states correcting public signs and "other venues where innocent eyes may be befouled by the vile stains on the delicate fabric of our language," according to the Teal website, jeffdeck.com. Asked if it had all been worthwhile, he said: "Certainly! There are a lot more people out there now carrying Sharpies [a brand of marker pen] around with them."
At the Grand Canyon National Park, the men had found a 60-year-old sign with a misplaced apostrophe and a missing comma. They duly whipped out Tipp-Ex and pen, and made the corrections. They then spotted that "immense" was spelled as "emense". They were shocked, but stayed their hands. Mr Deck later wrote: "I was reluctant to disfigure the sign any further.... Still, I shall be haunted by that perversity, "emense" in my train-whistle-blighted dreams."