Dear All Who Replied,
Firstly thankyou for doing so.
The main part of the 'bus.' is relatively ok (thankfully I caught it before it did 'real' damage), the spring 'flap' part that comes the main bus. is what I wish to cure, as also part of the front of the bus.. Obviously what has happened is that the chroming or tinning on the 'flap' part has been corroded - but the steel behind is ok and sound - but there is residue siting in minute pitting that needs neutralising. There is no rust, just a slight covering of blue oxide. I have a mini drill with numerous miniature wire brushes, so getting the surface stuff off is not too much of a problem (though fiddly), but it is not possible to get into all the minute surface pitting that will still hold micro amounts of acidic 'content'. WD40 is a good idea, as also Pet. Jelly and Vaseline - the former and latter does seem to sort such things out on machy. elec. terminals. However, on this scale of things I haven't done anything until consulting learned Mayhem members
Thankfully the 'corrosion' has not affected too much (no elec. connections to the bus. and nothing eaten away too much), and the situation is recoverable/repairable, it just needs stabilising. I will wait a few days more in case there are any other suggestions, but I think keeping it bone dry, then wiring brushing, then WD will do the job.
Thankyou again for your suggestions/opinions. Regards, Bernard