premise: How do you use a tin can to juice baneberries?
hypothesis: Punch holes in the bottom of the tin can with a hammer and nail. Clean the can, then place the berries into the can. Hold the can over a bowl and press a cup that is slightly smaller than the can into the can and down on top of the berries. Pull the cup back up a little, and then push it into the berries again. Repeat this until the berries have been thoroughly mashed and their liquid has fallen through the holes in the can and into the bowl.