I did a science experiment with the kids. White Vinegar vs Citric Acid in water solution to remove rust. Citric acid is easy to come buy - used in home wine making.
Tried them both at 5% (White Vinegar is already 5%).
Citric acid is amazing. Just leave in overnight. No nasty chemicals... easy to get rid of.
Used it on loads of nuts & bolts now. I then tried zinc plating at home - but that's another story.
Also - this was the best thing I found to undo stuck stuff:
http://www.halfords.com/motoring/paints ... pray-400ml
It's like WD40 - but also freezes. Only thing which would budge my bottom bracket - and a 3 foot long breaker bar!
Good luck.
