Melty eye mod conflict solution
You will need- a problem that looks like this:
OH GOD THE HORROR
A backup of the mod that added the new race that gave you the problem.
This problem comes from installing a mod that changes the base eye textures and models to something where the left eye and right eye use different textures. I use Elaborate Eyes, which you can get here. This works fine unless you have another mod which adds an extra race, playable or unplayable, which uses the existing eyes. What ends up happening is that Oblivion finds eye MODELS based on the definitions for the race, but finds eye TEXTURES based on a race-independent procedure. So Oblivion sees its old models and maps BOTH the new textures - left eye AND right eye onto them at the same time. Melty-eye ensues. Ew!
To solve this problem, first open install the TES Construction Set. It will install to your base Oblivion directory. Open it up, then open the mod that adds the new race(s) that is the problem. (Click the folder button at the top left, then find your mod from the list that pops up, click it, click "Set as active file", and click OK. I'll demonstrate with moDem's City Life mod, which you can get here.
Then open the entry for one of the new races you want to edit. Go to the Face Data tab and click one of the entries for Eyes (Left/Right). Your eye mod's eye meshes will be stored in the Data/Meshes/Character folder. If you are using Elaborate Eyes, the folder is Data/Meshes/Character/Nequam.
Select the appropriate eye model file from your eye mod's folder. Make sure you repeat this process for both left and right eyes. Click OK and then click the save button in the main window. Your ESP has now been modified.
The next step is to get the right texture onto your new model. This part is easier. Do the same process as with the model, except choose Eyes in stead of Race under the Character dropdown menu. Pick the eye options your new race has available to it and associate them with the appropriate texture files from your eye mod. For Elaborate Eyes, the file is Textures/Character/Nequam and the files you probably want are humNrmGreen.dds, humNrmBlue.dds, and humNrmBrown.dds to replace eyeGreen, eyeBlue, and eyeBrown respectively.
If you are unsure, look at an example of the race you are altering. You can find an example in the Object Window, which should load when you first open the Construction Set. Find the example in the NPC hierarchy under the name of the new race.
Repeat this for all the new races your mod adds and all the eye textures they use. Once you are done, you will not have melty eyes any more!