Yeah sorry, not a lot of explanation there- I had 4 attempts to post the pic. I used standard rust converter straight from the bottle (30% phosphoric). It ate through the carbon and fuel stains in about 10 seconds . There was a tiny little bit of foaming which I suspected was the acid getting into the alloy, so I worked quickly and washed it off with detergent thouroughly, several times. (I was slack with this on the area that I tested it on and white Al oxide showed up in about 15 min) If you want to soak it overnight I would definatley dilute the acid down to 5-10% or possibly less.

I had tried everything- carby clean, metho, turps, degreaser and none of them worked that well- I tried the rust converter out of frustration

Not as good as a professional acid bath, but better than anything else I have seen (although gasket stripper is supposed to work pretty well too) From what the guy in the carby shop said, their bath is a mixture of hydrofluric acid and other stuff (he wouldn't say what) - Hydrofluric is one of the most dangerous chemicals known to man (+ you need a licence to use it), so I'm happy so stay well away from that gear!!

Beauty, thanks for that. We use hydroflouric for cleaning Stainless after welding and it is nasty stuff, it turns your skin yellow and rips through tissue and builds up in your bones eventually causing cancer, we have cans of special spray if any gets on your skin.

You must be using a highly diluted version of HF. A decent splash of Conc. HF will kill you over the space of a couple weeks- usually they amputate the limb ASAP and sometimes that works, but usually the victim just hits a coma & kacks it. It's used in geologly for digesting rock samples. From memory (did an OH&S course), the flouride stays in your system and acts as a catalyst to degrade phosphate based structures (bone is calcium phosphate, but also phosphate in proteins).

Quote:

Better you than me mate, I'd be wearing head to toe overalls and a face mask.

or at least some rubber gloves.