Polo is the least else you need to use ethereum exchanges that charge 0.005-0.01 ETH which is again expensive as ETh price is above 750-800. You can use something like mercatox where you can select the price of withdrawal but it again starts at 50k satoshi as your transaction may never get confirmed if you use a small fee. The best option for you is only withdrawing/trading your amount/tokens in ETH and then sell it at polo in BTC with a total fee of 50k satoshi.
thanks, i am doing the same with dogecoin, trading on cryptopia (220k withdraw fee in satoshis, i need to use cryptopia because this is the only exchange for electroneum we are mining), sending to poloniex for 3 doge fee, selling doge for BTC and withdrawing. I think the best is to cumulate a lot of BTC and withdraw at once.