How to Clear Caches in LG G2 Running Lollipop 5.0.2
If you have root or a custom recovery, you can do this using a terminal emulator or adb. BusyBox required.  

shell@android:/ $ su
root@android:/ # cd /data/dalvik-cache
root@android:/data/dalvik-cache # find -type f -exec rm -f {} +
root@android:/data/dalvik-cache # cd ../data
root@android:/data/data # find -type d -name '*cache*' -exec rm -rf {} +

Note that in Android L, ART has fully replaced dalvik, including cache directories (/data/dalvik-cache). The reason for not creating a /data/art-cache is probably for compatibility concerns.