surfologist87 is right. Unless you made a nandroid backup, the only way to remove mods is to reflash the ROM. That will overwrite them with what the ROM originally came with. Keep in mind that you don't need to wipe data. All it will wipe out is any mods you flashed, and it will restore the stock kernel if you changed it.
The reason this is the case is because warm updater cannot just delete a mod. When you flash a mod, you're flashing modified framework files. Those files simply replace the ones that were there before. They generally include certain aspects of the current ROM (theming for example) along with the mod you want. It's like this because most things you want to change are bundled in the same framework files, and have to be flashed all at once. So, in order to remove a mod, every single mod developer would have to supply both the mod and the original framework files that were modified for the mod. That means double the flashable zips, plus the fact that some mods overwrite each other, so you'd end up wiping out other mods, more than likely. The save everyone the trouble of potentially hundreds of flashable mods, you must just reflash the ROM to remove all mods, then reapply what you wanted to keep.