I have also been looking for a use for this old sweater. Perfect opportunity to up-cycle both items!
I shoved the jar into the sleeve with the jar opening at the cuff end of the sleeve.
I then tied off the sleeve with a piece of string.
Next, I chopped off just beyond the string.
I then sewed around the bottom of the jar.
Next I chopped off the string, leaving a gathered circle underneath the jar. Then I Mod Podgedthe raw edges to stop them from fraying.
Then I slapped on an circular scrap of fabric to cover up the ugliness.
If I had more patience, I would have liked to sew something on the front. Instead, I finished by wrapping the jar opening with some rope and finishing it with a pretty bow in the middle. So for now, I am rocking the nautical look but it can easily be changed :)