Start by sorting through the leaves and discarding any yellow, slimy, or damaged pieces. Place the spinach in a large bowl or sink filled with cold water and swish gently to loosen dirt and grit. Let it sit for a minute so sediment falls to the bottom, then lift the leaves out — avoid pouring the water through the spinach.
Lay the leaves in a salad spinner and spin until mostly dry. If you don’t have a spinner, spread the leaves on clean kitchen towels and pat dry. Excess moisture speeds spoilage, so aim for dry but not paper-dry leaves.
Store in the fridge in a breathable container to balance humidity and airflow. Options:
Keep in the crisper drawer at 34–38°F (1–3°C). Check and replace damp paper towels every couple of days. Properly cleaned and stored spinach should stay fresh 5–7 days depending on initial quality.