Liquidate collateral position

To liquidate a collateral position select one of the 'undercollateralized' positions and press the red close button on the right of the position. Example below.

Liquidation close button

In the new window confirm closing the position by selecting remove. Make sure you have enough tokens to close the position. Example below.

Liquidation position close

After confirming remove, agree with the payment using your web3 wallet. In this example metamask. Example below.

Liquidation web3 wallet

Once the transaction is send wait for it to be included in the blockchain. If you refresh the page the collateral position will be removed. The received ETH will be available in your wallet.