We will separate common salt, sand and iron filings from their mixture by using a magnet, filtration and evaporation.
First, a magnet is moved over a mixture of iron filings, sand and common salt. In the process, iron filings are separated by the magnet. After that, sand and common salt are mixed in water. While salt dissolves in water, sand does not. So, sand is separated by filtration. On heating the filtrate, all the water evaporates from the mixture and salt crystals are left behind.