Melacha #33: MOCHEK - ERASING

Av Melacha: Cleaning markings off the beams in order to write new markings.

Principle: Erasing for a constructive purpose, i.e. for the sake of new writing.

1. Torah prohibition -- For the sake of new writing:

Erasing or destroying letters, markings, signs, pictures or ink, thereby creating a surface for new writing.

2. Rabbinic Prohibition -- Not for the sake of new writing:

Erasing or destroying writing in such a way that it doesn't leave a surface for new writing (e.g. by cutting through a letter) is Patur aval Assur.

Therefore, when letters of one substance exist on the surface of a different substance -- e.g. icing on a cake that spells words or a picture, or food packaging that has writing or logos -- it is prohibited to break or slice through the writing. Cutting between the letters is permitted (though some are careful to cut and separate the letters before Shabbat).

3. Permitted -- Not an act of erasing writing:

When only one substance is involved -- i.e. the writing is raised (embossed) or engraved (e.g. a cookie or chocolate bar) -- it is permitted to destroy it by breaking or cutting. (Though it is prohibited to engrave the writing.)

If the whole cookie or chocolate bar is in the shape of a letter or picture (e.g. shaped like a fish), it is also permitted to break or cut it before eating. (Though it is customary to bite directly into it rather than to break it first.)

In any case, it is permitted to eat the letters by breaking them with one's mouth, since this is considered an act of "eating" and not "erasing."

In the case of stamped or other writing on the side of a book, where opening the book would break the letters or make the writing illegible: It is permitted to use the book, but it is preferable to use another book if available.