What is considered a muck

[The Dean]

Any forward action resembling a muck, is a muck.

[DrStrangepork]

At my games, a muck is as follows:

• If cards are thrown in a forward manner outside of a player's immediate playing area, and both cards land face up on a "live" portion of the table (which includes the board but does not include the muck pile or chip rack), that is not a muck.
• Any other forward motion is a muck
• Any cards that are touched by the dealer in any way are mucked
• A verbal announcement of a fold causes those cards to be mucked