Tokens are locked into the Ring until it's filled

[HarryR]

There is no way to recover tokens from an unfilled Ring.

Some options are:

1. Make the remaining deposits to fill the ring and unlock funds
2. Allow removal of a specific participant (and their token) by providing their non-anonymous signature

The first is potentially expensive and an observer will see that the same gas payer has filled the ring.

The second will link the gas payer to the key owner.