public static void setTokens(final int tokenPublicPrefKey, @Nullable final String tokenPublic, final int tokenSecretPrefKey, @Nullable final String tokenSecret) {
        if (tokenPublic == null) {
            remove(tokenPublicPrefKey);
        } else {
            putString(tokenPublicPrefKey, tokenPublic);
        }
        if (tokenSecret == null) {
            remove(tokenSecretPrefKey);
        } else {
            putString(tokenSecretPrefKey, tokenSecret);
        }
    }
this method is to be solely used for auto-fixing GC username, see MainActivity.UpdateUserInfoHandler
main/src/main/java/cgeo/geocaching/settings/Settings.java