Anodise

yes

 

Yes you can, but sometimes the surface finish suffers, may need adjusting (polishing)

 

yes you can and it isn't to expensive as well.

henk!!!

 

Yes you can but . The more you do the more honeycombed the metal becomes and I think it possibly is not so good or can effect the surface of the metal as the acid used obviously removes a small amount each time you do it .. So say if you kept re anodising a fork tube I'm sure I was shown one and each time it was done got thinner and thinner ...