Line a medium sized glass bowl with a white dishcloth or floursack cloth (I use these). Pour in the regular yogurt either raw or pasteurized.

Tie up the ends of the cloth with a rubber band and attach to the knob or handle of an upper kitchen cabinet with the glass bowl directly underneath.

Allow the liquid whey to drip into the bowl for about 10 minutes. About 1/2 cup of whey will have dripped into the bowl for each 12 oz of yogurt in that amount of time.

Carefully remove the bag of yogurt from the kitchen knob and place into a clean bowl. Unfold the ends and scrape out the Greek yogurt into a clean glass container. 

The remaining whey in the first bowl can be refrigerated in a small glass mason jar for about 6 months. It can be added to smoothies for a raw whey boost or used in a variety of fermented foods recipes.