CStackCacheManager::Clear

function Clear($entity, $id = false)
{
	if (defined("BITRIX_SKIP_STACK_CACHE") && BITRIX_SKIP_STACK_CACHE)
		return;

	if (!array_key_exists($entity, $this->cache))
		$this->Load($entity);

	if ($id !== false)
		$this->cache[$entity]->DeleteEntry($id);
	else
		$this->cache[$entity]->Clean();
}