Thank you for the comments regarding my sewing room and the scissor find. It is good to know there are sewing elves/brownies in the house!
Eileensews asked me to share how the rust was removed from the scissors. This was the work of my husband, closely supervised by the children as a school holiday project.
They used information from this post on a woodworking forum. The rust is removed by electrolysis.
First my husband stripped the wires from an old mobile phone charger, and attached alligator clips to the wires.
Then he made a solution of 1/3 cup bicarbonate of soda (baking soda)NaHCO3 in 2 litres of water, placed in a non metal container (yoghurt tub). This is probably a stronger solution than necessary, but overkill does not hurt in this situation.
The scissors were attached to the black clip, and placed in the solution. The red clip was attached to a scrap piece of mild steel (you could use any old bolt or washer), and also placed in the bucket, not touching the scissors. Then the charger was plugged in, sending a current through the scissors, and much of the oxidized metal (rust) is transferred tot he sacrificial anode (scrap metal on the red clip) which needs to be scrubbed off occasionally. It took about 48 hours and 2 scrubbings of the sacrificial anode to remove the rust from the scissors. Naturally the circuit had to be placed away from general family traffic whilst in use.
My family are very useful as a sewing support team.