A: Easiest way, that should be tried first and foremost: Go to recovery (preferably Amon RA Recovery or TeamWin's Recovery Project) and select Wipe all user data/factory reset. Do this step 3 times. At this point you can flash the ROM.
Now, this is all you should have to wipe because the Cache and Dalvik Cache are included in the Data partition (which is wiped under this selection). Other partitions are wiped during ROM installation. However, it is never a bad idea to go in and manually wipe these other partitions manually.
To perform a super ultra wipe, perform the following steps with Amon RA Recovery:
1. Click wipe ALL USER DATA/FACTORY RESET.
4. Click wipe CACHE
5. Click wipe DALVIK CACHE
6.Click wipe DATA
7. Click wipe SD_ANDROID SECURED
8. Click wipe BOOT
9. Click wipe SYSTEM
10. Click wipe BATTERY STATS
Perform each step 3 times.
Now, install the ROM and enjoy an error-free SOS ROM.
Thanks to Team Swag member pfcland for the latter tutorial