[morzh]

Don't even think about "restoring" a power chord. First of, even if you owned your own wire plant, that would require stripping the old insulation and then covering the old copper (which is the same as the new copper so what's the point) with replacement insulation and cloth jacketing.
Just get whatever looks and feels like the appropriate one for the periode.
In short, power chords, unless they are in good condition and just a part of them needs a patch, get discarded, and the further you throw it the better.