Spread a white, cotton dishtowel evenly in the bottom of the glass bowl (I use this one). Scoop or pour the yogurt into the middle of the dishtowel.

Gather up the ends and tie securely with the rubber band. Attach the rubber band to a knob or other fixture on one of your upper cabinets with the bowl underneath to catch the drips.

Allow the liquid whey to drain out of the yogurt. This will take several hours. Greek yogurt will take about half the time to drain as regular yogurt.

When there is no longer any whey dripping out of the yogurt cheese bag, remove the bag from the kitchen fixture and place on the counter. Remove the rubber band and lay the dishtowel out flat. 

Scoop the yogurt cheese which will have a firm but moist texture into a container (preferably glass), affix a lid and refrigerate.