Corrosion on gilded keris blade

[krissman]

Several of my keris blades display gilded naga motifs. One of them is showing copper sulfate corrosion between the gilding and the iron. I have been able to remove the corrosion from one side fairly easily with toluene on cotton swabs but thought before doing the other I would ask if there might be some better or safer method. Also, I would appreciate learning how future corrosion might be prevented. Finally, I am wondering if the "gilding" on this blade might in fact be brass, not gold. Two images are attached. One shows the hilt and the other shows a section of the blade where corrosion can be seen. If anyone has any thoughts, I would be grateful to have them.

This is my first post with photos. I cannot tell if they will come through. If they don't I will try again. Thanks for bearing with me.