https://www.lowrance.com/contact-us/
Check out the FAQ's if they don't fulfill your query eventually there should be a means of contacting a representative. I am amazed you are having this issue and perhaps a rep can shed light as to why this is a problem.
Before I was gung ho on dielectric grease, I had a few incidents of corroded FF plugs. Multistrand fishing wire works well for cleaning the corrosion out of female plugs. Cut 2" long pieces, insert them in the female holes, and twirl. As the wire twirls, it unravels and cleans out the corrosion. The dielectric grease might lack the resistance to cause the wire to unravel, but the grooved form of the wire will gradually remove the excess grease, similar to a small drill bit. If you try this make sure the wire is multistrand uncoated.
https://www.basspro.com/shop/en/amer...ductextensions
Dielectric grease is an excellent corrosion protector of electric connectors. Don't wreck a good thing by putting a solvent on the connectors that will prevent the grease from doing it's job.