Locate enscript reported non-printable chars

I'm making a postscript of a bunch of C code, and enscript reports I have 2 non-printable chars [ 91 pages * 1 copy ] left in a.ps 2 non-printable characters non-printable character codes (decimal): 128 153 However I couldn't find these chars with grep grep -r $'\231' * grep -r $'\200' * Is there a way to let enscript report which lines contain the non-printable chars?