We just wash fruits and veggies under cold water.

Personally I wouldn't use anything special to wash them, like vinegar etc. they do need a little bacteria in their body or else your bird will be susceptible to more germs in the long run... just like humans.

Antibacterial anything isn't good for humans, let along birds, so I don't recommend using that either.

Also, with the fruit thing, it is important to wash all fruit, including melons etc. when you cut into the fruit you are bringing the germs and pesticides into the fruit, so it's always a good idea to wash fruits and veggies even if you don't eat the skin/outside.
I just wash everything the way that I would do if I were going to eat it.