1. can be decomposed into two arbitrages: A, 35,820 yuan to buy near-month 10 lots and 36 180 yuan to sell far-month 10 lots, and then close positions at 35,860 yuan and 36 130 yuan respectively; B, 36 180 yuan sold 10 lots in recent months, and bought 10 lots at a distance of 36,280 yuan, and then closed positions at 36 130 yuan and 36,270 yuan respectively.

A. The opening spread is 360, and the closing spread is 270. Because it is the arbitrage of buying low and selling high (selling arbitrage), the spread reduces the profit, so the profit of an arbitrage is (360-270) per ton * 10 lot * 5 tons per lot = 4,500 yuan.

B, the opening spread 100 yuan, the closing spread 140 yuan. Because it is buying high and selling low (buying arbitrage), the spread expands the profit, so the profit of B arbitrage is (140-100) *10 * 5 = 2000 yuan.

So the net profit of this butterfly arbitrage is 4500+2000=6500 yuan (excluding the handling fee).

2. Calculate the profit and loss of the near, medium and long months respectively, and then add the profit and loss to get the net profit and loss. Profit and loss in recent months: (35860-35820) *10 * 5 = 2000; Mid-month profit and loss: (36180-36130) * 20 * 5 = 5,000 yuan; Far monthly profit and loss: (36270-36280)* 10*5=-500 yuan; Total; 2000+5000-500=6500