Records can be either sealed or "expunged" which is erased.  Generally, an arrest that results in a acquittal or dismissal can always be expunged.  But states limit the type of conviction that may be expunged or sealed, like excluding certain felonies, etc.  If you qualify you must file a petition for expungement in the courts. It is best that you go an seek help from a criminal attorney that does this in his or her regular course of business. It can be a difficult thing to do and if it is done incorrectly it can be time consuming to do again.  Good luck.