Playing AA & KK vs a maniac

[RickA]

Playing a full table .5/1 at Gaming Club against a maniac. I found the seat on his left.

Dealt AA
Maniac EP2-raise
Me - 3 bet
LP - call
maniac calls

Flop 7h Ks 6s
maniac - bets
me - raise
LP - folds

Turn 4d
Maniac - checks
Me - raise
he checks

River - 6c
Maniac - checks
Me -bet
Maniac - raises
I call
he took it down with 68s. Did I play it OK.

Exactly 1 orbit later (good seat)

dealt KK
Utg - raises
Maniac call
Me - 3 bet
BB - called
utg & maniac call

Flop 4s 7d 6c
utg - checks
maniac - bets
i raise
BB folds
utg folds
maniac 3 bets
i call

Turn 7 h
Maniac bets
I call

River
5d
He bets
I call
he turns over 35o to win with st8.

i know he can't win long run playing these hands, I least I think I know he was up $60 at a .5/1 table but can I defend my hands better?

Thanks

RickA