Q:

Accidental ETC to ETH wallet

I accidentally sent ETC in Poloniex to an ETH wallet at Jaxx [two days ago] Poloniex has opened a support file, but no response yet. Is there a way to recover the ETC that is out in the ether somewhere?

A:

Since the receiving end is a Jaxx account, that means it's a simple private key, part of a Hierarchical Deterministic (HD) wallet tree.
Jaxx uses the same seed for all of the currencies it supports, so if the owner of the Jaxx account (you?) activates the ETC wallet, the funds should just show up in the Jaxx UI. If not, that could mean it's a very active HD wallet where you iterated through a bunch of addresses on the ETH branch. In that case, use a tool like MyEtherWallet to browse the HD address tree to find the buried address to which the funds were sent.
To use MyEtherWallet to work with your Jaxx wallet, first some precautions: you're going to be entering your private key into a website, so you should do some due diligence to make sure your funds remain safe:

Don't do the following on a computer you don't trust (no library computers or internet cafes)
Don't do the following on a computer that doesn't have an up-to-date virus scanner (do a scan and be reasonably sure there's no keyloggers or other bad stuff lurking)
Don't do the following in a public space (don't want people looking over your shoulder or security cameras recording your screen)

Go to https://www.myetherwallet.com, and verify you have landed on the proper HTTPS site for MyEtherWallet ("https" in the address bar, green lock shows in the browser, and certificate details show it belongs to "myetherwallet.com").
Now that that's all set, in the top-right of the MyEtherWallet interface, change the network drop-down to ETC (since that's the currency you're hunting for). Then go to the "Send Ether and Tokens" tab, and click the "Mnemonic Phrase" option. Enter your Jaxx backup phrase into the text box and submit.
In the dialog that pops up, choose the topmost option (m/44'/60'/0'/0), which is labeled as Jaxx ETH, since that's where you accidentally pulled the address from. In the lower half of the dialog, you should see the address you accidentally sent to, and it should show an ETC balance. If you don't see it, use the "More Addresses" link to scan forward in your address list. Once you find it, select it and click "Unlock your Wallet".

Then you can use the form onscreen to send the ETC to the proper address in your Jaxx wallet, so the UI can find them.

