So, you used up the last of the peanut butter and it is time to recycle the jar. However, there is still a film of peanut butter inside the jar. You don't want to put dirty plastic into the recycling bin and you don't want to just throw it out. The peanut butter is difficult to clean out. Sure you can use a lot of hot soapy water to get it out, but that is just wasting more resources than you are saving by recycling the jar. I humbly present the following solution.
Step 1: Tools Required:
Heavy duty kitchen shears or another cutting implement.
A Ruby. More on this later.
Step 2: Cut Jar
Cut jar in half with shears or other cutting implement. Obviously, be careful not to cut yourself. The middle of the bottom of this jar was pretty thick so I had to cut around it. Don't leave any real sharp or jagged edges.
Step 3: !Caution!
Do not attempt this with glass jar, unless your name is Wang Chi. Even then, you should probably think twice about it.
Step 4: Cleaning
Now it is time to use your Ruby. This is Ruby. If you do not have a Ruby available to you, borrow someone else's. If you cannot borrow a Ruby, consider adopting one from a local shelter.
Step 5: Intermission
Grab yourself a beverage.
Step 6: Cleaning Progress
Dog tongues are very efficient.
(bonus points if you can spot one of my other instructable projects)
Step 7: All Clean
Remove the peanut butter jar from your Ruby before it begins to chew the plastic. Place in recycle bin.
You get clean plastic for recycling and the dog gets a treat. Win-Win.
Props and respect to my ex-wife who came up with this idea.