For poached eggs: Add 4 cups water to the large skillet; add vinegar. Bring mixture to boiling; reduce heat to simmering (bubbles should begin to break the surface of the mixture). Break an egg into a custard cup or small bowl and slip egg into the simmering water. Repeat with three more eggs, allowing each egg an equal amount of space in the water. Simmer eggs, uncovered, for 3 to 5 minutes or until whites are set and yolks begin to thicken but are not hard. Remove to a bowl of warm water. Repeat with remaining four eggs.