Aluminium

what do you use to neutralise corrosionbeforepaintingaluminium ,isrust neutraliserssafe on ally ! .

Tergo rust killer. Yes.

Dont use rust neutraliser, it is acid and will cause more corrosion.

I would go for physical removal with a bronze wire brush, scotchbrite pador a blasting media , followed by the appropriate chromate primer.

Heavy corrosion on aluminum parts is a sign of impurities in the casting materials ie high silica content. Cleaning by scraping back helps short term. Zinc Chromate (yellow base coat on outboards of the 70's era) was the preferred primer of that time but now there are more modern alternatives. Z.C. is now regarded as highly toxic, being heavy metal based. If left unpainted it will oxidize badly again, such is the nature of the elements in the alloy casting. Electrolysis is another story.