Based on some investigation in Google Books, what books actually do is use a footnote: "blah blah [sic] blah" 1 1 [sic] in original. It's fundamentally the s

Based on some investigation in Google Books, what books actually do is use a footnote: "blah blah [sic] blah" 1 1 [sic] in original. It's fundamentally the same thing as clarifying "blah blah blah" (emphasis added) or (emphasis in original). Note that the purpose of [sic] is not to point out how clever you are to find an error, but to clarify for the reader that the text is copied accurately. Thus, the original question about putting a [sic] on a mistaken [sic] is not something that makes sense to do.