Useless an English teacher

The part-time teachers' room at the place I work on Tuesdays has a secretary. I have been using her recently as I've been cleaning up old student records and so on. I take her the papers with students' personal information on them, and ask to use the shredder. She always takes the papers and tells me not to worry about it, she'll dispose of it herself. I also give her paper that can be recycled or used again.

I am apparently not the only person who has been getting rid of old papers, because recently she has placed a couple of cardboard boxes in prominent view, with neatly handwritten labels, in which we can deposit student records and scrap paper to be disposed of. This is typical of her. She is a friendly, helpful person.

However, I am a little puzzled by the labels. I know she doesn't speak much English, but does she not realize that she is surrounded by English teachers, any of whom would have been happy to help her?

The label on one box says:

USELESS A PRINTED SYNOPSIS OF A LECTURE.

And the other one says:

USELESS A PERSONAL ITEM. REDUCE TO ASHES.

I was going to say something about this (after I'd turned off the grin that had suddenly spread all over my face), but then had the sudden thought that perhaps she had asked one of the Japanese teachers of English to translate the labels for her. I tried to think through the ramifications of the loss of face my correction could cause, but it was the end of a long teaching day and I was too tired, so I went home instead. Now I feel stupid. I should have just told her, quietly. I am useless an English teacher.

I'll tell her next week.