Rehabbing a peace lily

[kilroyscarnival]

We've taken on the care of some potted plants (and a cat) of a friend while she is away. Two of them are large peace lilies, which though otherwise healthy have been sun-scalded on most of the exterior leaves.

I'm hoping I can help rehab them. We placed them under a large tree in the partially shaded back yard (they were outside plants I think the whole time), and my plan is to gradually trim off the burned leaves allowing space for new growth, while not cutting it back too severely so that it looks thin or hacked.

Is there anything else I can do to help it regrow? I understand they don't want too much fertilizer, and I have no idea whether she used it or not. Other than the sunscald they look very full. Eventually I want to scoot them out of their pots to see if they need more room for the roots, aeration, etc. But I'm trying not to disturb them too much, especially in all this Florida heat.