Non-erasable chalk sounds like a counter-intuitive product, but it makes sense for certain classroom activities. The Teacher’s Desk, a site dedicated to tips for fifth and sixth grade teachers, describes a grammar and spelling lesson where students proofread passages written on a chalkboard. The teacher takes the class through each line and marks up the words as needed. But if you teach several periods of English and you erase the marks you made at the end of each class, you end up erasing the passages too, which means you have to re-write the passages for each period you teach. Non-erasable chalk can come in handy for writing out those passages and protecting them from your eraser. Here’s how you make it and maintain it:

• Mix a solution of sugar and water.
• Soak some regular chalk in the solution, take it out, and let it dry. Now it’s non-erasable.
• Don’t worry; non-erasable chalk mark isn’t permanent. You can still wipe it off with a sponge and water.
• To make sure your chalk stays non-erasable, put it in a sealed jar after you’re done using it. If that doesn’t do the trick, simply re-soak your chalk in sugar water.

So does it really work? I haven’t tried it myself, although other sources seem to agree that sugar water can help make your chalk smudge-resistant. If you’re feeling adventurous, try this “recipe” out for yourself and leave a comment to let us know how it turns out.