Karen Wilson, of Rugby, discovered the money in an envelope between the cushions of a two-seater sofa.
It dropped out of the back of the green sofa and contained £1,305 in bank notes, reports the Daily Telegraph.
Relatives of the late owner of the sofa were traced thanks to a Gift Aid form they had filled in and were delighted to hear about the money.
Ms Wilson said: "The sofa originally belonged to an old lady who passed away. So there is no way they would have known the money was there.
"I rang them and said 'do you think you've lost something?' and they replied 'No I don't think so'. When I told them what had happened, they were over the moon. They were absolutely stunned.
"When they came in the grand-daughter was in tears - she just couldn't believe it. The daughter said her mother used to hide bits and pieces around the house. But never anything like this."
The family, who wished to remain anonymous, donated £100 to the British Heart Foundation as a goodwill gesture.
"Usually we just find a few pence lodged at the back of sofas, but in this case an envelope dropped out stuffed full of cash," added Ms Wilson.
"I couldn't believe it, I just started laughing. My colleagues were as surprised as I was when I opened the envelope which was full of bank notes. We weren't tempted to keep it though."
Karma reigns true for these fortunate few. We all have dreams of winning the lottery or finding a bag of cash. Is that going to make our lives suddenly fulfilled with promise and prosperity? Sounds like just one more immediate gratification to me. Might as well find a bag of crack.
When will we stop looking to phunny money debt notes as the answer to our woes? When those debt notes are pieces of paper valued at what pieces of paper are valued at.