[The Philpott]

I posted some pics ages ago of refurbing corroded Avo battery contacts (The 15 volt ones)
Of course with older equipment you have better options for undoing or drilling out the contacts allowing them to be immersed. Lemon juice, brush off any remaining verdigris then oak in distilled water, then wipe with petroleum jelly. I was surprised how well a 20 minute soak in lemon juice removed the green stuff- it penetrated right into the pitting.
Dave