If I transfer bitcoin into Trezor that has been on a paper wallet since 7-31-17. Can I still get BCH and BTG? If I transfer bitcoin into Trezor that has been on a paper wallet since 7-31-17. Can I still get BCH and BTG? Trezor has a coin-splitting tool, but it says that I had to have held Bitcoin in my Trezor on before August 1st.
The reason you cannot use the coin-splitting tool is that the private key of your offline wallet is where the new BCH and BTG coins were created at the time of the fork. By sending your BTC to Trezor, you are only spending the BTC part, the BCH and BTG are still associated with your paper wallet's key.

After your send the BTC to Trezor, you need to import your paper wallet's private key into a Bitcoin Cash and Bitcoin Gold wallet, and then send the coins to a new fork-specific addresses from there. Make sure to send the BTC away first before you start exposing your paper wallet's key, to ensure you do not lose the BTC in the process. See How to claim Bitcoin Cash &amp; Bitcoin Gold from paper wallet for more information.