I would not use lemon on a razor. Acid = bad.

I also have seen people get either goo or light staining on razors from camilla oil. I don't know if it's a question of the oil quality/source/whatever, but I don't like the stuff. I'd use either nothing or mineral oil. Also tufglide seems to work very well.

I had to de-goo a few once. I used soap and hot water.