Been playing with the cashu-ts library, and have built an updated version of Cashu Redeem that works with v4 tokens and gives "change".

It lets you redeem a Cashu ecash token and get paid to your lightning address.,, just like paying cash into a bank account.

You can also use this tool to pay a lightning invoice using ecash, with change returned as a new ecash token.

Let me know what you think!