The simplest way is buying new altcoins 
x2 profit is easy but it's risk.
x2 profit is easy but it's risk.Yes it is simple but the profit you get will not as much as trading using bitcoin. Ant the risk is higher than do trading with bitcoin so what I do suggest is better convert all your altcoin back to bitcoin and start do trading with bitcoin but its all up to you and the decision is in your hand
The problem is privacy. To trade with FIAT you need to give your credentials (usually involving proof of bill, ID scan and so on) to some exchange that you shouldn't fully trust (we are still on the early days). I dont want my shit being sold to third parties...
so basically the best way to trade BTC anonymously is against other alts.