CWM wipe data/delvik cache question topic

Sony Experia U Locked Bootloader CWM Touch Recovery 5.5.0.4

When I do a Wipe data/Factory Reset and Wipe Delvik cache nothing seems to be wiped

I run several Root Explorers and the folders are still full of files


Delick cache is still full of .dex files

Data folder is still full of all types of files

I deleted all the files once and my phone messed up

Am I looking in the right folders

Strange thing if I don't do Wipe data/Factory reset in CWM some new roms i try don't load or work properly

When I do a backup am I doing a nandroid backup in CWM?

Thank for any help