Here's how to remove custom contracts and tokens in Ethereum Wallet / Mist

  1. Open up the Wallet UI
  2. For tokens: run this command in the console: Tokens.find().fetch().map(function (m) {Tokens.remove(m._id)})
  3. For contracts: run this command: CustomContracts.find().fetch().map(function (m) { CustomContracts.remove(m._id) })

To list the contracts and tokens:

  1. CustomContracts.find().fetch()
  2. Tokens.find().fetch()

Note: This has not been tested for safety in mainnet. Run only in testnet.