Her lessons really started when the school invested in a new sound system in the hall. "It's a four-speaker affair," says headteacher Susan Morton,who nominated Mary for our flowers, champagne and chocolates. "It's quite a fantastic piece of equipment."
Mary does lots of "mopping and buffing - but mainly mopping", and she's happiest doing it to music. At first, using the new system, she played "endless pan pipes", but then peripatetic music teacher Mr Mackey intervened with CDs of Sixties music: the Beatles, the Shadows, rock and roll. Mary cordons off parts of the hall while she mops and buffs so children can enjoy the music as they troop out to playtime. "It's not as if she's blasting out the school, but she certainly mops in time," says Susan Morton.
She's known as "Auntie Mary" to many of the children and has real nephews and nieces in the school (pictured here). Lower Darwen has special provision for 15 children who are hearing impaired and prides itself on a friendly, helpful ethos. "Mary really loves this school and it shows," says the head. "She wants us to succeed and will do anything to help. You only have to ask."
Her practical skills and energy came in handy recently when the school ordered furniture for a computer suite. "It was half-term and she was fetching, carrying, and clearing all the mess away afterwards."
When the library needed a new carpet, and the old one appeared to be glued to the floor, she was the first with a sharp shovel scraping it off. "At the end, Mary's still there, making a cup of tea and telling you that everything will work out fine." Every school needs a Mary.
We know there are heroes out there. Tell Sarah Bayliss, TESFriday editor, about yours at the address on the left. Flowers kindly supplied by Marks Spencer