a lot of coil springs have rust on them, have you a friendly garage who can put the car on a lift so you can have a look. so you can see how bad they are. if not to bad some work with a wire brush and a touch of paint or even grease will sort it.
I wouldn’t waste your time on the springs. If they are already rusted, grease or oil won;t do that much. Better off putting a bit aside for new springs. Factor on £40 a corner to fit if you can’t DIY, and £60 for a pair of pattern springs.