From Sydney Anne Holt:

I remember that once, one of the guys took off his shoes and was on the mylar checking when it was discovered his socks were damp and his toes were erasing the drawing as he moved along. Fortunately, it was caught very soon so the rework was minimal. We had a good laugh over it.

And for some background and context:

Sydney Ann Holt worked as a layout designer of the 6502 microprocessor. The following Q & A recounts her time and efforts at MOS Technology working on the 6502. Sydney was the only woman who worked in a design capacity on the 6502, and, in fact, was often the only woman doing so at subsequent companies throughout the 1980s as well. The following Q and A recounts her experiences working on the 6502 at MOS Technology and elsewhere.