We (creators of DTMF.io) have put together a simple process for getting access to the BCH associated with your Bitcoin private keys.
It's now live at
https://www.coinfork.io/Basically, we sweep your wallet on both blockchains, and transfer both your BTC and BCH associated with the wallet to addresses of your choice. There is a small (0.5%) fee associated, to cover costs of operating the service. We also pass on the transaction fee on both blockchains (to be clear, we pass on the recommended transaction fee from Bitcoin Core for BTC and from Bitcoin ABC for BCH).
After the sweep+transfer (which we aim to complete within one hour, but usually it takes less time), there are no funds associated with the private key you sent us any more on either blockchain, because they have all been transferred to the addresses you provided.