You can't delete automaticaly unless you are using the Pro version, with the home version they can be sen't to the chest.
Silent Mode
Personally I don't use silent mode, because I want to know what is going on with my system. If someone is getting so many warnings of virus infection, infected emails, etc. that they become intrusive, then it is time to review their security practice - filter emails at source, delete from server rather than download them, etc.