Repurpose an AC adapter

[RichardCranium]

I have an hp adapter, I'm unsure from what, but believe laptop. I'm intending to repurpose it for use in an electrolysis tank, for rust removal on vintage/antique tools. When I cut the pin from it and strip the black coating I have 3 wires, 1 white, 1 black, and 1 blue.... The black wire I imagine represents what for my purposes if you imagine it like a battery, the negative. The white wire the positive, I'm unsure the blue, I'm fairly computer illiterate, but possibly a sensor. Any help/feed back would be much appreciated

 

[hang-the-9]

Probably the ground.