The nearest expiration date for Ethanol T2 FOB Rdam Including Duty (Platts) Futures (May 2018) is Jun 5, 2018.
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 Ethanol T2 FOB Rdam Including Duty (Platts) Futures (May 2018) before Jun 5, 2018.