Having a good platform is also a part of profitability:
US crude oil: fixed margin400USD in one hand/1000Bucket, Fluctuation0.04USD return, fluctuating0.01USD profit and loss10USD, no spread, no overnight fee.
Silver: Fixed margin600USD in one hand/5000Ounces, fluctuating0.016USD return, fluctuating0.005USD profit and loss25USD, no spread, no overnight fee.
US Gold: Estimated Margin600USD in one hand/100Ounces, fluctuating0.4USD return, fluctuating0.1USD profit and loss10USD, no spread, no overnight fee.
Natural gas: Fixed margin400USD in one hand/10000mmBtuFluctuation0.004USD return, fluctuating0.001USD profit and loss10USD, no spread, no overnight fee.
Meijing Copper: Fixed margin600USD in one hand/25000Pound, fluctuation0.0020USD return, fluctuating0.0005Profit and loss12.5USD, no spread, no overnight fee.