I used Evaporust allot, works especially well on small parts. The biggest downsides I see are that it loses it's strength pretty fast and if the part is not absalutely clean of grease or grime it doesn't do much to the dirty areas. Normally not an issue but some parts are not so easy to completely degrease before using it. Notice how the parts they chose look like pretty clean parts with dry orange rust? That's what it works best on.