Yellow-Browning Leaves

[paigee229]

Hi,
I've already posted on here once about an Phal that I'd left in the sun and had gotten yellow leaves, but I think I'm still doing something wrong, or perhaps there's a bigger problem? The yellow parts have spread, and are browning. I've posted pictures of it. Does one ever cut bad parts off of the leaves? I'm tempted, because they look so unhealthy and the unyellowed parts are still such pretty green.

Thank you again to anyone that can help, and thanks for your time!