...until yesterday when my wife brought me a dry erase board with dry erase pen markings that would not come off the board! She complained that brand A dry erase pens would wipe off of this board with no problem, but brand B dry erase pens would not wipe off of this board but would wipe off of any other dry erase surface we had!
I went about trying every cleaning trick I knew, from bleach to alcohol to oil and any other method you could think of, all to no avail.
Then an idea came to me! I took brand A dry erase pen and scribbled over the markings of brand B dry erase pen, took a dry rag and wiped, VOILA!! It came off no problem! My reasoning for trying this you ask? The answer is obvious to those who have spent a large amount of time watching Star Trek or any of its spin offs!

matter and anti matter can not occupy the same space at the same time!

I can't believe I even considered it in that light!