I linseed-oiled the inside of some frames to protect them against rust. Some of it got onto the outside because I was a bit over-generous with it. The oil that got out onto the paintwork did set quite hard and seems quite durable but, because it remains slightly tacky, it attracts and holds onto dirt like an absolute bastard. My white frame now looks really grubby (I don't care because it probably makes it less nickable). I can't see any reason why it would be different on raw steel, so "approach with caution" would be my advice.
I linseed-oiled the inside of some frames to protect them against rust. Some of it got onto the outside because I was a bit over-generous with it. The oil that got out onto the paintwork did set quite hard and seems quite durable but, because it remains slightly tacky, it attracts and holds onto dirt like an absolute bastard. My white frame now looks really grubby (I don't care because it probably makes it less nickable). I can't see any reason why it would be different on raw steel, so "approach with caution" would be my advice.