(Q) cleaning wiping phone - best effective method

hey guys,

which is the best method to clean your phone before flashing a new rom, or maybe bringing your phone to the state it was just after flashing a new rom. i tried data factory reset, wipe cache , wipe dalvik with kernels we have here and i found remainents of zip files i had flashed after setting up my rom and using newer mods. i dont want to format system, preload all the time.
which is your perfect, effective method ? speedmod kernel and its recovery or phillz , then which version ?
thanks