According to the Dinitrol can it treats existing corrosion and delays its progress; AFAIK Waxoyl is also full of corrosion inhibitors. I wouldn't rely on them to treat really heavy patches, but if it's just the normal orange surface dusting you get in a frame it should be fine.
These seem like rust proofing sprays. Which I'd need anyway so thanks. But I'm not sure they'd treat existing rust would they?