I just found another method that doesnt require any apps other than Root Explorer and RAR for Android.
(1) Open Root explorer and make a new folder in the root of your internal storage called app and if you are using kitkat then also make a folder named priv-app in the same directory if needed.
(2) Find the app you want to odex and copy it to the corresponding folder that you just made. (If it came from /system/app copy it to /sdcard/app and if it came from system/priv-app copy it to sdcard/priv-app) I will use /system/app/Apollo.apk as an example. Copy /system/app/Apollo.apk to /sdcard/app
(3) Move /data/dalvik-cache/system@app@Apollo.apk@classes.dex to /sdcard/app
(4) Rename
system@app@Apollo.apk@classes.dex to Apollo.odex
(5) While you are still in /sdcard/app, long press on Apollo.apk then press Open With then select APPS, and scroll down and select RAR.
(6) Put a check mark in the box next to classes.dex and press the delete icon.
(7) (Optional) I reccomend making a copy of the original apk that still contains the classes.dex in a directory of your choosing. (EX: Copy /system/app/Apollo.apk to /sdcard/app/backup/Apollo.apk)
( 8 ) Delete Apollo.apk from /system/app then copy or move Apollo.apk and Apollo.odex from /sdcard/app to /system/app and set the permissions to rw-r--r--
Done