This sounded just too cool: write on a hard boiled egg with a special ink made of vinegar and alum powder, let it dry, peel the pristine shell and your message appears written on the white albumen below… I read about this somewhere and even found this video… It’s all over the web, with lots of different people claiming to be its author… It’s a fake! It doesn’t work! I tried everything: I used ammonium alum and aluminum sulfate. I tried applying the “paint” on a raw egg then cooking it as instructed, but I also tried painting a pre-cooked egg and leaving it overnight. I tried pre-treating the eggshell by soaking it in vinegar. Nothing. Don’t waste your time or eggs on this one (above you can see one of the victims of my experiments).