Books expert Clive Farahar started rooting around when he was invited to open a Cotswold Care Hospice shop in Minchinhampton, Gloucestershire.
"Our shop manager showed him the annuals, thinking they might be worth a couple of quid," said Marcus Green, chief executive of the hospice. "Clive thought they might be worth rather more."
Farahar put the charity in touch with a book auctioneer, which will put the annuals up for sale in February. They are now expected to fetch several hundred pounds, but were likely to have been sold for a couple of pounds each in the shop.
"Sometimes there is treasure in charity shops for people who look hard enough, and sometimes there is treasure in them for staff that look hard enough," said Green.