The Power of Apple Cider Vinegar for Rust Removal

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No. That is a slug on the block from the salt, vinegar and rust.

The second picture is after pressure wash. It flash rusted before I could blow dry it.

There was still some rust in the cam tunnel and my pressure washer is a hot water unit that plugged up the gun while I was washing it. So back in the tank for the moment.

I mixed 4 gallons of cider vineger with a 1/2 container of table salt and 40 gallons of water.
Gotcha. I thought the first pic looked cleaner but it makes sense now that you say it flash rusted.