Just do a flush by Hulda's method and flush will solve the problem.
Flushing hard stones stuck in bule duct is 100 times easier then flushing hard stones from gallbladder.
Just do the flush immediately, do not wait! Waiting can be dangerous, as that stones may obstruct pancreatic juices and may cause pancreatitis and even death!
Do flush immediately, flush is 100 times safer then surgery or ERCP!