Following my father,s death  I inherited three planes and a sharpening stone. Can anyone please help me with the following questions

The planes…a number 5 Stanley,a number 4 Woden and a Stanley block plane .All the planes are in excess of 40 years old, have  surface rust and some deep scratches running along the length of the soles 

My questions

(1)The planes blades have a small amount of surface rust and slight pitting.Can anyone comment on the likely quality of these blades,is it worth taking the time to grind and resharpen them and importantly how far along the blades do I need to remove the pitting

The deep scathes on the soles is it worth taking the time to remove these using wet and dry paper attached to a piece of float glass or is there a quicker method to remove these scratches which  are about the thickness of a pencil line 

(2) The sharpening stone

The stone is in excess of 40 years old in a wooden box   and is a combination stone .The edges of the stone are slightly damaged but the stones appears to be reasonably flat

I can remember in the mists of time reading an article suggesting initially soaking an old stone in petrol to clean it up

My questions

What is the likely quality of his stone ,is it worth salvaging ,does soaking it in petrol initially make sense

Finally Please note i live in the United kingdom, does have any bearing on the likely quality of the planes and sharpening stone

kind regards

 Charnwood