Melacha #29 [30]: M'MACHEIK - SMOOTHING

Av Melacha: Scraping down animal skins.

Principle: Scraping or thinning a substance to improve its surface.

Toldot: Smoothing, scraping, or thinning a solid or semi-solid (for a constructive purpose).

1. Torah-prohibited substances:

a. Solids: Wearing down or scraping off a solid substance. It is therefore Chayav to sand down a rough block of wood. In addition, one may not use a bar of soap, or scrape down the leather soles of shoes (Patur aval Assur).

b. Semi-solids: Smoothing out thick creams and ointments, etc., in a way that thins them. Therefore, one may only smear such a cream on a wound in a case of danger to life.

2. Rabbinically-prohibited substances: Thin creams, or soaps that lack firmness.

3. Permitted substances: Liquids that are free-flowing. Therefore, one may use liquid soap or hand cream that pours freely.

4. Exception: Food may be spread out for the sake of spreading, but not for the sake of thinning. For example, one is permitted to spread peanut butter onto bread (i.e. for the purpose of eating it easier), but one is not allowed to smear avocado on a serving platter for the purpose of making it look nice.

It is permitted to squeeze food from a tube (e.g. ketchup on spaghetti), but not if you solely want it shaped nicely (e.g. cake icing).