1.   Discard any mussels that do not open.

2.   Discard any mussels that are broken or do not clamp shut when tapped.

3.   Discard any mussels that do not close when tapped on the counter.

4.   Discard any mussel that does not clamp shut.

5.   Discard any mussels whose shells are open.

6.   Discard any mussels that have not opened.