 Use slit tubing to cushion the separatory funnel in the ring clamp. Close the stopcock on the separatory funnel and position an Erlenmeyer flask beneath the setup, in case it drips. Into the separatory funnel pour the liquid to be extracted using a funnel: this prevents liquid from getting on the ground glass joint which can cause it to stick. Pour the extractive solvent into the funnel. Hold the separatory funnel so that your fingers firmly cover the stopper. Invert the funnel and shake gently for 10-20 seconds. Periodically "vent" the funnel (open the stopcock while inverted to release pressure). Never point the tip at someone while venting. Return the separatory funnel to the ring clamp, and allow the layers to separated. Remove the stopper (it won't drain otherwise). Drain the majority of the bottom layer into an Erlenmeyer flask. Stop when roughly $$1 \: \text{cm}$$ of the bottom layer is in the funnel, and swirl to dislodge clinging droplets. Drain the rest of the bottom layer, stopping when the interface is inside the stopcock. Label the flask (e.g. "bottom aqueous layer"). Pour out the top layer into another Erlenmeyer flask (and label it). Don't throw away either layer until you are sure you've accomplished the goal of the extraction.