Cleaning corroded contacts in fishfinder power cable

The contacts in my fish finder power cable are getting corroded (bluish powdery film on the contacts). The contacts are female (recessed) so that I can't just wipe them. Is there any way to clean it out, i.e. immersing it in some type of solution?

Try spray it with W40 first then apply some dielectric grease to prevent rusting in the future.

baking soda....make a paste...us a toothpic or something the get the paste into the holes, even a thick gauged wire would fit. Maybe use the male end to get the paste into the holes. Let dry and scrap or brush/ pic clean. The soda neutralizes the corrosion. Then you'll want to keep that area loaded with dielectric grease all the time.
should work and good luck!