The 15-second rule
If you find the accident more than 15 seconds later, any scolding or punishment is completely pointless. Your dog will no longer make the connection.
No reaction
Ignore both the accident and the dog. Don't sigh, don't look at him.
Clean up the smart way
Use a mix of 50% white vinegar and 50% sparkling water. Avoid bleach, which encourages the dog to go in the same spot again.
💡If your dog treats the cleaning as a game (grabs the mop, jumps about), clean up out of his sight.