A Left-Handed Solution
I am left-handed, so I used to end each day with an enormous black and blue smudge down my hand from writing on the overhead projector. I no longer have this problem since I started leaving a lightweight work glove next to my projector. Whenever I start notes with my students, I put on the glove. It looked pretty silly the first day or two, but we just laughed about my appearance and now even my students will put on the glove when they write at the overhead.