This stuff is bloody magic, much much better than WD40.
It's normally priced about £13-15 for 458g aerosol, and you need to use a very small amount at a time.
"The US Navy carried out tests using ACF-50 on the jets on their Aircraft Carriers. They found that ACF-50 so significantly reduced the corrosion they had previously experienced they now use ACF-50 all the time!"
http://www.acf-50.co.uk/motorcycle.htm