Purchased a 5 ltr container of Evapo-rust, thought I'd give it a try. It's more expensive than I was told around $66 plus postage, but it works and it was fast acting. Light rust on some bolts was gone in about an hour and heavy rust on springs and shocks I left over night and they came out rust free. There is doesn't appear to be any damage to the base metal, it just acts on the rust, and the supplier says it can be reused until it loses potency. And best of all no smell or need to find a place out doors to keep it.
