[Looneyland]

I need to know what to FLUSH my radiator with thats NOT toxic? Does anyone have any idea?
I deal with mechanics a lot & one asked me how to flush his radiator without killing his dog to get rust out. I know to use 'Sierra' brand to replace the antifreeze, but what can get the rust out & not hurt the critters.

I was very happy he even THOUGHT to ask!! Usually, hindsight is 20/20

Thanks,
Laurie, RVT