GSA crash bars "rust" removal

[baiker 2]

The leading edges of the (aluminium/alu finish) crash bars on my GSA get a sort of brown rust-like stuff on them.  Before I autosol the whole issue, :

Anyone know what this is ?
Anyone know how to get it off ?
Anyone know how to keep it off ?

 

[BiG DoM]

 

[BiG DoM]

 

[baiker 2]

 

[baiker 2]

 

[BiG DoM]

 

[baiker 2]

 

[BiG DoM]

 

[Ice2]