Not that I understand the issue, but...I don't think it's the rust that's so valuable. It's the age marks and patina. If you take an old tool and clean it up so it looks new, you've destroyed the quality which a collector values.

If you run across a signed James Black Bowie, (dream on!) leave the cleaning to an expert conservator who understands how to handle antique knives. The right approach will make it look better without ruining it for high-value collector resale. An amateur with naval jelly and a wire brush will turn a priceless heirloom into a worthless piece of junk that everybody will condemn as a fake.