"Sandy" wrote in message
...

My conclusion is that although the vinegar and the salt-and-vinegar
cause some of the loose rust to fall off the very rusty iron, the
treated surface is by no means cleaned. The appearance is not even
perceptibly changed. I can't determine if one works better than the
other, but from the colours of the solution and the rust and the
lesser effervescence, I would conclude the the salt impedes the
dissolution process.

Interesting, despite what the others say! Your test about jives with my
results, the most notable difference being the nearly clear vinegar/salt
solution and the dark red (in my case) vinegar only solution. I would say
that the iron did come clean by using the vinegar solutions, but required
some brushing to really get all the rust off. I think it came cleaner than
it would have had I not used the vinegar, but maybe there are better
mechanical ways of doing that, or using a little muriatic acid and being
very quick to rinse it off.

dwhite