code: public static void removeValue(String registryName, String key) {
  		Sysprop registryObject = readRegistryObject(registryName);
  		if (registryObject == null || StringUtils.isBlank(key)) {
  			return;
  		}
  		if (registryObject.hasProperty(key)) {
  			registryObject.removeProperty(key);
  			CoreUtils.getInstance().getDao().update(REGISTRY_APP_ID, registryObject);
  		}
  	}
docs: Remove a specific value from a registry.
  @param registryName the name of the registry.
  @param key the unique key corresponding to the value to remove (typically an appid).