try searching the archives for citric acid.  a member did a insitu clean
and flush using citric acid a few years back.  citric acid can be made
from powder.  the powder is sold for use in food.  it goes by the name
sour salt.  it comes in two types sodium and calcium salts.

http://en.wikipedia.org/wiki/Sodium_citrate

http://en.wikipedia.org/wiki/Calcium_citrate

it is available where a wide selection of spices are sold.  i use it for
cleaning rusty metal tools and parts.  maximum pH of solution that i have
been able to make is in the 2-3 pH range as i remember.  i don't have my
notebook at this computer but i can look it up if need be.

additionally white vinegar sold in stores for food use contains acetic
acid.  my understanding is that the majority of white vinegar sold in this
country is an industrially produced acetic acid.  the pH i measure for the
stuff i buy from the grocery is pH 2.  cleans metal as good or better
than my citric acid solutions.  the main reason i say that is that the pH
of the acetic acid when cleaning metal stays lower (more acidic) for
longer.

jonathan

On Wed, 11 Mar 2009, Zoltan wrote:

> I have a couple of radiators that are otherwise in good condition other than that they are a little clogged up with whatever stuff.
> I was wondering what is the best way to clean them inside to make them work new again.
> I know, I can buy them new for a good price, if any of you want to tell me that.
> Anyone?
> Zoltan
>
>
>