Depending on what exchange where those coins being listed but mostly when we do talk about converting to eth then most likely this is an ERC20 token which you would directly make conversion.Usually these tokens are being listed or traded most of the time in DEX. Etherdelta,Forkdelta,IDEX and other decentralized exchangers.Just be sure you do follow exchangers instructions on how to trade up or convert those tokens to prevent such loss of money.Common mistakes committed by newbies if they aren't able to see tutorials on how to do it. Trading up on decentralized exchangers is somehow confusing for the very first time.Therefore we should really be careful.