I think I would be tempted to try rusty end squashed in a vice first and try to get some rotation out of it, failing that cut the rusty bit off just shy of the stainless and used a stout screwdriver to force the rusty bit to crumple inwards the only other way is to use a die grinder to grind a strip through inside of the old steel till you meet stainless then just rip it out .......a few methods there for you
