Provide advice on how to accomplish the following goal. Give ONLY the advice, no other words or explanation.
For example:

Answer: <advice, as short as possible; a single sentence!>.

Goal: how to make butter in a mason jar
Pour heavy cream into the mason jar, filling it half-way full. Screw the lid on.    Shake mason jar for approximately 5-7 minutes. After the first 2 minutes you'll have whipped cream. Keep shaking until you hear that a lump has formed inside, and shake an additional 30-60 seconds after that.Remove the solids from the jar. The remaining liquid is buttermilk. You can save that for other recipes, or discard it. Place the solids into a small bowl. Pour cold water over the butter and use your hands to squish it into a ball. you now have butter
Shake heavy cream in a mason jar until butter forms, then drain off buttermilk.