I just did the electrolysis thing on an old knife I found in the pasture. An old Barlow.

It took off all the rust and left some black stuff on the blades, it also knocked off most of the silver color on the 'Barlow' caps.

The blades aren't a uniform silvery color, but there isn't any rust left. Still trying to get all of the black stuff off.

Just used a 12v converter with two alligator clips. Clipped the positive to a nail and the negative to the knife. Put it in small plastic bowl filled with water and a couple tablespoons of table salt.

About 30 minutes in, the water was green and had some funky stuff floating on it.