Steps:
1. Iron nails can be separated from the mixture by handpicking (if the number of iron nails is low) or by magnetic separation.
2. Now from the mixture of oil, water, tea leaves and salt, tea leaves can be separated from the mixture by filtration.
3. From the mixture of oil, water, and salt, oil can be separated from the mixture by sedimentation followed by decantation.
4. Salt can be obtained by evaporation of the saltwater.
5. The evaporated water can be condensed and then retrieved.