To make clear ice, the key is to use a method called directional freezing, where water is frozen slowly from one direction (typically top to bottom) to push out impurities and air bubbles that cause cloudiness. Here is a practical step-by-step process:

1. Use filtered or distilled water; boiling is optional but can help remove impurities.
2. Use an insulated container like a small cooler or a styrofoam box to control freezing.
3. Fill the container with water and place it in the freezer without a lid, so freezing occurs from the top down.
4. Freeze the water slowly, usually for about 18-24 hours, until most of the water is frozen, but a small amount of unfrozen water remains at the bottom.
5. Remove the ice block and discard the unfrozen water (this water contains impurities).
6. Cut the clear ice block into cubes as desired.

This method results in crystal clear ice because air bubbles and impurities are pushed to the bottom and out of the clear ice block during freezing.

Additional tips:

• Do not freeze water from all sides at once (like in regular ice trays), which traps air bubbles and causes cloudiness.
• Clear ice melts slower and looks visually appealing in drinks.
• Silicone molds with holes can help release trapped air bubbles when making individual cubes.

This approach is the most reliable for making clear ice at home, suitable for cocktails or any beverages requiring aesthetic, clear ice cubes.