Product review (5 stars): some tips while using this, use gloves!
Be patient and in a good mood while applying this product!  It takes time!  Make sure you have good ventilation otherwise the smell might make one sick.  But it does that it says it does.  I am leasing a home and I didn't want to invest into a new rack to a unit that isn't mine, so I got this instead, TERRIBLE rust spots, some almost completely thru.  This did a trick, I might need to order a second bottle just because the rust is so bad.

Some tips:
Follow the directions before ripping it out of the package.
WEAR gloves!  this stuff takes FOREVER to get off your fingers, I can barely type this review.
Open a window or turn on the fan, smells strong.
Lay newspaper or do it somewhere where drips won't get on tile, wood, ext...  this stuff is hard to remove.

I'll update my review soon with photos before and after.