My shower curtain was never something that crossed my mind as a potential survival item but it sure can be used in a variety of ways if you’re short on supplies. One or two ideas are stretching it a bit (like the makeshift greenhouse) but the others are certainly ones to consider and since the shower curtain is waterproof most of the other ideas make sense:
“If you plan to use a shower curtain that has been used in the traditional way as a shower curtain you will want to get rid of any mildew and hard water deposits on the curtain before packing away. One simple way is to lay the curtain out flat and spray with undiluted white vinegar. Let the vinegar work for 30 minutes and then rinse well with water, and hang to dry. You do not want to roll or fold up a plastic curtain with mildew on it and then stick it in your pack.
Most standard shower curtains are more or less 72 by 72 inches. The plastic is heavy enough to sew/stitch together, and yet can be easily fitted to objects such as your body.
Drape the shower curtain over your head and shoulders with the grommet side to the ground. It would be good to have a magic marker handy at this point. Put a dot on the plastic where it touches each shoulder. Remove the curtain and put a small piece of duct tape over the dot on each side of the plastic….”