Two kinds of clean

Original non-fiction-style practice text.

The brass band polished its instruments before the town procession. At the rehearsal, one new player spent longer rubbing his cornet than practising the difficult entry. From the front of the hall, its surface caught every light. The conductor asked him to put the cloth away for the remaining ten minutes.

He explained that a spotless instrument was welcome, but it could not produce a reliable entry without the player's preparation. The cornet's brightness would be visible in the official photograph. An early note would be audible to everyone along the route. The two kinds of readiness needed separate attention.

The player worked through the entry slowly with the neighbouring musician. By the end, he could begin on the correct beat. He still checked the cornet before leaving, but did not treat its reflection as a report on his rehearsal. The instrument had become cleaner in one sense and his playing more secure in another.

Explain the distinction the conductor makes between the instrument’s appearance and the player’s preparation.