With a sieve.
The smarties are big enough for you to pick it up with your bare hands?? I'm guessing the smarties you are talking about is the sweets..
get a strainer to get the sand out silly :)
You should use a magnet to separate iron from sand. Iron is magnetic, so it will be attracted to the magnet and easily separated from the sand. A strainer would not work in this case as it would not be able to separate the two based on their magnetic properties.
You can separate them by filtration and it would help because when you add water the sand would stay because you would have to add cold water so that the sand will stay and the salt will go through.
There will be a color and taste difference between the two.
it would be like thou sand
Iron can be separated from sand using a (electro)magnet.
To do this you will would normally use a large wire filter where holes are set at about the size of sand. By vibrating this net area it sifts out the sand leaving rocks in the netting - It can be undertaken by multiple operations where holes in the netting become smaller so filtering page to small grains/rock. A crude method is using a rake to drag away large rocks from sand
Sublimation
Add water, It separate woodchip(float) and sand(down)
In solution, the salt will be dissolved in the water, the sand and iron will settle to the bottom of the container. Separate out the water, evaporate the water and the salt will remain, separate the sand and iron filings with a magnet.
A simple filter would be suitable for separating sand and water. An alternative would be to evaporate the water, leaving the sand behind.