If you're an ETH holder then after the recent controversial hard fork (HF) you're now also an ETC (Ethereum Classic) holder too! If you have your holdings in an exchange like Poloniex then you've probably already seen your new ETC balance and can easily trade it with other currencies.
But if you have your holdings in a wallet like Mist or Geth, then trying to get access to your ETC is harder than you might think. I tried to run Geth on the classic chain and move my ETC to Poloniex, but my ETH balance from the same address moved too!
After banging my head against the wall for a while I saw a tweet about the Shapeshifter.io splitter tool and decided to give it a shot.
It requires you to first create two brand new addresses, one in the ETH blockchain and one in the ETC blockchain. To do this you need to run two separate instances of your wallet, but you can do this on separate computers or run them one at a time to avoid complication. You don't need to wait for the blockchain to sync to create a new address. Be sure to back up the keys to them both!
You enter your new ETH and ETC addresses into the tool, then click start and it will give you an address to send your coins to. You send your coins from your original address - either your ETH or ETC balance it doesn't matter as it will be deducting from both anyway. The coins will appear in both your new addresses and are then completely separate from each other :-)
Send just a tiny amount at first to check your new addresses in the block explorers for both chains (e.g. etherchain.org for Ethereum and gastracker.io for Classic) to see if your coins turn up. If they arrive no problem, then you can click "start" in the tool again to get a new address and send more. If they didn't turn up, check your process to find the problem. Note that it can take a few minutes for the process to go through.
I've used it about ten times now with lots of different sizes of balance and it's worked really well. They do take a 0.25% fee for each split.