I know that there are years after ... I've had the same problem and today I've found the way to claim it ... finally :)
I've got old BTC from before fork on Bitcoin (so before 01.08.2017). I've been struggling back then (just after fork) how to send it to some other wallet or market to get my cash back ... unfortunately back then I wasn't able to find the way.
From tomorrow I've done the same research again and I've come into this page. I was quite sad when I couldn't find the answer how to do it.
Today finally I've done it :)
What I've done:
On Bitcon Core I've exported my private key (this only can be done with old legacy wallets ... I've got backup of that one). For doing that you need to go to console and write commands:
a) unlock wallet:
walletpassphrase "<here you put your password to the wallet" 600
b) export private key:
dumpprivkey 18wX2UUqNn3W6MLq2urHNMjvEXaZr3hYoL
That (18wX2UUqNn3W6MLq2urHNMjvEXaZr3hYoL ) is my BTC/BCH address. If anyone want to thanks me - you can send some BTC or BCH there :-)
After that you've got your private key to your legacy wallet. That one we will use later on other tool
Download the Electron Cash. I've downloaded windows portable version from https://electroncash.org/
Warning: I've had warning message from Norton Antivirus that the program doesn't have correct signature. Here I was quite not sure ... but as I wasn't able to get my money back ... I still tried to use it.
There wasn't any other warning from NV so I've continued. I've done some tests before I've imported correct private key.
When you start the program, you should create new wallet and then choose 3rd option: Import BCH addresses or private keys.
If you will put here the public BCH address - you would have read-only view for transaction. If you would import your private key - you will be able to send BCH to different wallet.
Send money :)
And that's it ... worked for me :-)
Good luck :)