code: @Override
  	public synchronized void delete(Context context, AuthProviderType type) {
  		
  		SharedPreferences prefs = context.getSharedPreferences(PREFERENCES, Context.MODE_PRIVATE);
  		
  		String authData = prefs.getString(USER_AUTH_DATA, null);
  		
  		Editor editor = prefs.edit();
  		
  		if(!StringUtils.isEmpty(authData)) {
  			 UserProviderCredentialsMap map = jsonUtils.fromJSON(authData, UserProviderCredentialsMap.class);
  			 
  			 map.remove(type);
  			 
  			 editor.putString(USER_AUTH_DATA, jsonUtils.toJSON(map));
  		}
  		else {
  			editor.putString(USER_AUTH_DATA, jsonUtils.toJSON(makeDefaultUserProviderCredentials()));
  		}
  		
  		editor.commit();
  	}
docs: /*
  (non-Javadoc)
  @see com.socialize.api.SocializeSessionPersister#delete(android.content.Context, com.socialize.auth.AuthProviderType)