some one asked about pencil marks How to remove them. Had you thought of using a eraser. I did try using one that architect use. they use one that does not leave smear. I did use one and it did remove the pencil mark.the one i have is STAEDTLERMARS TECHNIPLAST. and it is old a fresh one could do a better job. at least it is worth a try.

thanks, that's so good to know.