The nearest expiration date for Singapore Jet Kerosene (Platts) Dubai (Platts) Crack Spread Futures (Sep 2017) is Sep 29, 2017.
The best time to sell a futures contract is when you've already made money on the investment, but still have plenty of time left before the expiration date. Thus, a good option would be to sell Singapore Jet Kerosene (Platts) Dubai (Platts) Crack Spread Futures (Sep 2017) before Sep 29, 2017.