I know this has come up several times, I just wanted to to give you guys some comparison pics of how this stuff works and looks. Sanding the rust off does not get into the crevasses of the metal like naval jelly or phosphoric acid does. I just did my car a few weeks ago. I used straight phosphoric acid (or Ospho to some of us) without diluting it and applied it with a paint brush, you can buy the acid at homes depot, lowes etc. I have never diluted it, I think it worked faster, and if treated quickly it wont harm the metal. Since the acid is a liquid, it is very runny, so I put it in a plastic cup and brushed it on in sections, if you dab it, it will foam up and somewhat stick to the side of the door for example, let it sit for about 10-15 minutes and started scrubbing using stainless steel pads. Once the metal looks clean, I washed the metal with soap and water using a wet rag, if you hit bare metal with water and dry it, it will NOT start to flash rust, someone asked me about that last time. If you look at the dash thats the way the doors used to look. On the really rusty parts it will be necessary to do it several times. I also used stainless steel pads from Wal-Mart (you can find those in the house cleaning section of the store), not a wool pad, the stainless steel pad really cuts into the rust. And thats it, I took side by side pick of how the rust gets converted to a white powdery substance after sitting all night, if you apply another coat of the acid and start scrubbing you will get clean metal.