OUT_OF_POLYS_

Tucked inside an old cassette tape you find a note.
The yellow paper with faded edges feels like it's been there for years, it says:

14 8 9 13 _ 9 13 _ 1 C C _ 14 8 1 14 _ + _ 8 1 16 5 _ C 5 6 14 ;
1 E 4 _ E F 17 _ 9 14 * 13 _ F 15 14 _ 14 8 5 12 5 _ 6 F 12 _ 14 8 5 _ 17 F 12 C 4 _ 14 F _ 13 5 5 ;
+ _ F E C 19 _ 8 F 10 5 _ 19 F 15 _ 3 1 E _ 5 E A F 19 _ 9 14 _ 1 13 _ D 15 3 8 _ 1 13 _ + _ 4 9 4 ;
10 C 5 1 13 5 / _ 14 12 5 1 14 _ 9 14 _ 17 9 14 8 _ 3 1 12 5 ;

What could it mean?