Cleaning Internal Radiator Residue
 

I am setting an automotive radiator for use in my wc system, and have noticed some whitish/yellowish residue on the inside of the radiator :(

Does anyone know how to remove/clean this stuff off ?


The rad core is aluminum, with poly endcaps.

It's from a 1993 Acura Integra.

Re: Cleaning Internal Radiator Residue
 

The few I've used I've just taken to a radiator shop, with good results. I know they used to use oxalic acid - and may still, but a lot of "standard" chemicals have disappeared (IMHO a good thing - I'm a lot more interested in breathing and drinking potable water than I am in overclocking my PC).
For a home treatment, I'd try straight white vinegar, then rinse well with distilled water.