The safe way is more premium hands. The most rewarding way is to play more hands with him, period. That is if you really know how to exploit him.. even maniacs have some sort of thinking pattern they follow. Like they will bet straight draws, gutshots and flush draws like the nuts, such as open push the flop or call an allin with it (remember here, this is stupid play but they WILL suck out on you 1 in 3 times).. exorbitantly preflop raise their middle pocket pairs (because they don't know how to play them postflop).. or they always bet into you if you show weakness.. etc.

If you can pick up a 'quirk' like he overbets his bluffs and bets his real hands lighter (so that you would call) then you can clean out the maniac.

Another very exploitable quirk is if they really like to hammer signs of weakness. Be sure to stop value betting your monsters and slowplay them! Then very hesitantly call his bluff overbets.. somewhere along the line you'll stack him with a made hand vs air.

A third common quirk one is when they tend to shove it allin when they don't really know what to do.. like they have JJ and the flop has a K, or they have a flush draw and you bet the pot, or they hit TP on a lowish flop (like A6 on a 246 flop).. they don't know what to do there, so they just push. This is more common than you might think in sucky players! If they know what their hand is worth, like AA on a 57K rainbow board, a set, and so on, then they start slowplaying or value betting etc. If you're up against one of those "shove when not sure" maniacs and you can identify em as such, this is very exploitable also.

If you are really totally clueless about the maniac's thinking pattern, better just stick to premiums..