Use the magnet to remove the iron- Spread the chalk powder, naphthalene and iron mixture on a flat surface. Wrap the magnet in the paper towel. Use the magnet to remove the iron by pulling it across the surface of the mixture. The filings stick to the magnet while the chalk and salt are left behind. Remove the paper towel from the magnet to collect the filings.

The mixture of chalk and naphthalene is separated by the process of sublimation. When the mixture of chalk and naphthalene is heated, then naphthalene sublimates and chalk is left.