Yes, you can move money between Jars (those Jars not opened with merchants featured on the app) and between Jars and your HyperJar Wallet. To move money from a Jar tap on it from the Home screen and tap withdraw and then choose a destination. To move money from your Wallet tap the card, then Send and follow the instructions.
You cannot move money from Merchant Jars back to your Wallet or personal Jars. The money has to be spent with the merchant or gifted to another HyperJar Member.