To receive Neo gas from my Neo tokens, I transferred my Neo tokens from bittrex to a web-based Neo wallet, neowallet.cn. Seeing my Neo generating gas continuously is pleasing, but I couldn't claim the gas generated. Initially I thought that I needed to wait for it reaching to a threshold, but that was not the case. After some tinkering and searching, I figured out couple of ways to workaround this issue.
Option 1: On the neowallet webpage, click the receive button, copy the receiver address, then go back to home tab, and send 1 Neo token to yourself. Once that token is received, you can claim the gas. Although to claim gas next time, you need to repeat this procedure.
Option 2: Download a desktop Neo wallet, such as NEON (download here: https://github.com/CityOfZion/neon-wallet/releases). The current latest version is 0.0.5, and earlier versions didn't work for me. Go back to the neowallet webpage, click the receive button, and copy the private key, then you can use it to log into NEON wallet, and claim the gas there.
Good luck!