So...somehow I managed to accidentally delete some vanilla static objects and I saved my mod, unknowing about the deletion until I just now realized it. So now my mod has the ceiling tiles used in almost every Ayleid Ruin set to be removed. How can I undo this? I heard I could use TES4Edit to do this, but I can't figure out how.

You could as well just open your ESP in the CS's Data Files menu and go to the details there before actually loading it. This shows you a somewhat hard to understand listing of everything your mod changed. Pressing DEL on any of those entries will make it ignored on your next load, and when you store your mod then these changes will be gone. That's manually cleaning your plugin of dirty edits.

I really don't know what I'm looking at when I open the Details window, but I do see several Ayleid Ruins listed under the "CELL" type. Would deleting those restore the ceiling tiles and fix my problem?

Open the mod in TES4Edit, and navigate to the Static block in the plugin.

Normally, you don't ever modify any vanilla records inside this block (editing pre-existing objects in this block is not a very good idea), so all you need to do is find the Ayleid Ruin static objects that your mod is editing to delete (TES4Edit will highlight them bright yellow) and delete those records from the plugin.

That will remove any changes your mod makes to those statics, and this is a bit cleaner than flagging the records to be ignored in the CS.

Thanks guys.

I had to delete most of the Ayleid Ruins listed in the Cell blocks to restore the ceiling tiles to those ruins, but everything seems to be in order now. I'm going to have to be careful with what I'm deleting from now on. Thanks again.