Smoothing a rough or uneven surface constitutes the melachah of memachek and is forbidden on Shabbat. In the Mishkan, this melachah involved scraping the hides of the rams and the tachash to smooth them and remove any excess hair.1 Similarly, one may not sand down wood or scrub a pot clean using steel wool2 on Shabbat, for these actions serve to smooth the surface one is working with.

One often encounters the melachah of memachek through it’s toladah: memarayach. Whereas the av melachah of memachek involves smoothing hard and rough surfaces, memarayach refers to spreading and smoothing semisolid and pliable materials, such as putty.3 Materials that are less firm and easier to spread are not Biblically prohibited. However, the Talmud records the view of Rav4 who states that the Sages forbade spreading ointments or creams that are thick, because it is difficult to distinguish between the thicknesses of various substances. Based on this, one may not apply vaseline or other thick creams on Shabbat, but as we will see, there are some ways these things may still be used.

Vaseline and other Rabbinically forbidden materials may be applied to an affected area provided that they are not rubbed in.5 As such, one is permitted to dispense cream onto one’s skin and gently dab at it without actually spreading it. This dispensation does not apply to materials that are Biblically forbidden to be smoothed. For example, blu-tac or mounting putty may not be used on Shabbat even if one only intends to stick them down without spreading or smoothing them. The reason we are more strict with Biblically forbidden items is that we are concerned that one may end up transgressing a Biblical prohibition,6 which is far more egregious than violating a Rabbinic one.

The Magen Avraham7 writes that the melachah of memachek only applies to smoothing something that is meant to remain on the surface, which some authorities rely on to permit creams that become absorbed into one’s skin.8 Another scenario where this can be applied is with regard to brushing one’s teeth on Shabbat. Rabbi Moshe Feinstein9 says that using toothpaste is memarayach and forbidden on Shabbat. Rabbi Ovadia Yosef,10 however, permits it based on the Magen Avraham’s reasoning.11 He points out that toothpaste is not meant to remain on the teeth, it is only applied to help clean them, after which it is expelled from the mouth.12

Bar Soap and Stick Deodorant

Many halachic authorities forbid using a bar of soap or stick deodorant on Shabbat, because by using them one smooths the surface of the bar. It is difficult to understand, however, why they consider this to be memarayach; after all, the bar is perfectly smooth before it is used and one who uses it has no intention of smoothing the surface of the bar. Nevertheless, the prevailing practice is to be stringent and not use such things on Shabbat.13 The same ruling would apply to lipstick, lip balm and the like. Liquidy gels, creams, or soaps, however, may be used on Shabbat.14 These items do not bear much similarity to the Biblically forbidden items that are firm or semisolid, and they are therefore not included in the Rabbinic safeguard.

In general, memarayach does not apply to food, since food is perfectly edible without being spread and nothing is accomplished by spreading it.15 Therefore, one may spread avocado or butter on bread on Shabbat without any concern.16 If the food is being smoothed for aesthetic purposes, however, like icing to decorate a cake, it is forbidden because it is being done for a purpose that is not food-related.17