Those of a slighty OCD clean-freak nature will love this:

It’s a microfibre cleaning/dusting mitt. And it’s brilliant for cleaning the whiteboard with. No smears or marker stains! You don’t need to worry about looking a fool using it – you’ll never get the chance. My pupils argue over who wears it and gets to clean the board. It’s also washable, which makes it a bit more eco-friendly.

This one was from JML and I bought it from Asda for £2.99. You can get them from Amazon, ebay, JML etc.