Blue marks on battery

[Rosscoe]

Has anyone else seen these marks on their batteries? Bike is a Rail 7

 

[Razz1]

Has anyone else seen these marks on their batteries? Bike is a Rail 7View attachment 29949

None on my rail 7. I'll be watching thou.

 

[Beekeeper]

Copper corrosion of terminals. Different metals turn different colours when they corrode

 

[pgtips]

Yes agree is corrosion of the terminals.
Spray some electrical contact cleaner and make sure you dry well after washing the bike. Compressed air is best after cleaning the bike. You can pick some cheap compressors this days.