Would the soder line turning white indicate a possible flux problem?

[aquatimer]

There is a white line appearing on the soder line connecting the blade to the guard and I m concerned that it might actually be flux.
The knife in question is about 15 years old and A2 with a Black Phosphate coating.
Thanks in advance,
John

 

[RJ Martin]

John: Yup, my bet is flux/corrosion leaking out of the joint, which, incidently, probably isn't soldered anymore. You can try applying wet baking soda, then, rinsing it off after a few minutes. This will help neutralize the acid flux, but, probably won't get inside the joint.

RJ