code: public void clear(String nsid) {
      	Auth a =  this.auths.get(nsid);
      	if(a != null) {
              this.authsByUser.remove(a.getUser().getUsername());
      	}
      	this.auths.remove(nsid);
          this.authsByUser.remove(nsid); // in case username is passed.
          File auth = new File(this.authStoreDir, nsid + ".auth");
          if (auth.exists())
              auth.delete();
  
      }
docs: /*
  (non-Javadoc)
  
  @see com.flickr4java.flickr.util.AuthStore#clear(java.lang.String)