A professor at a nearby university recently contacted me with an unusual request for certificate repair. She said there was a major problem with a certificate she wanted to have framed. I agreed to meet with her (no promises - you can never tell with a problem like this if it is repairable or not.) The problem with the certificate was that she was listed as an MD, but she is a PhD. She hoped that I could turn the MD into MS (because she was also Master of Science) and add PhD behind it. I decided that the best I could do was to camouflage the parts of the existing D with paint while turning it into an S with black ink.
The week long seminar she had attended was taught by people who meant a lot to her, and some were no longer available to sign a new certificate. She wanted to preserve the bit of history that their signatures provided. Also, the lettering was a style I seldom do, by a different, unknown calligrapher. I would have to attempt to match the lettering as closely as possible. Professor Z had contacted the CDC who issued the certificate, but they only advised her that they could re-issue one (with different signatures and with her name printed since they no longer use a calligrapher.) They advised her to try to find a good calligrapher who might be able to help. In a Google search, she found me, but when I saw the actual certificate I feared it would not have a good result. The paper was not the best quality - thin and 'papery', not conducive to scraping ink off well without tearing.) To top it all off, the ink had smeared in one place - and I had no idea if I had any ink that would match up since this was a decade old.
Later as I began working on trying to eliminate the smeared parts around the M, I discovered that careful scraping was working. I was able to 'erase' the M pretty well.
It's not a perfect result, but it's not bad. It's better than we had thought could be accomplished. The Ph had to be narrowed a bit to fit the M's slot, and there is some ink residue from the M and the original smearing. I was afraid to try to scrape it any more than I had, and I had erased with a typewriter eraser and a white eraser until no more ink could be removed. I think when she has it framed no one will notice the repair. She is thrilled to have saved this piece of her history, and I am happy to have made a new friend.