We have explained that during Pesach, one may not retain any food items that are not kosher for Passover.
Mixtures
Just as one may not possess actual Chametz, such bread and rolls, on Pesach, it is likewise forbidden to possess Chametz mixtures, such as beer and whiskey which are Chametz derivatives.
This law is derived from a Mishnah (Pesachim 42a) which states that one who retains Chametz mixtures, such as a Babylonian yogurt mixed with breadcrumbs called “Kutach,” transgresses the Torah prohibition of owning Chametz on Pesach.
An Inedible Mixture
Nevertheless, a Chametz mixture which is completely unfit for human consumption, such as certain types of glue and cosmetics which contain some Chametz ingredients, may be retained on Pesach.
Cheese and Milk
There are certain cheeses that contain Chametz ingredients added throughout the cheese-making process. It is therefore imperative that one use cheese with a kosher for Passover certification on Pesach.
Some require special kosher for Passover certification for milk, however, according to the letter of the law, milk all year round is deemed kosher for Passover.
The Poskim nonetheless discuss what the law is regarding deriving benefit from milk that comes from a cow belonging to a non-Jew that is fed Chametz on Pesach. Halachically speaking, Maran zt”l rules (in his Halichot Olam, Vol. 1, p. 305) that there is room for leniency in this regard, especially when it is unclear if the cow is even being fed actual Chametz. Besides for Chametz concerns on Pesach, one may never drink milk which was milked by a non-Jew without Jewish supervision, for this poses other Kashrut concerns.
Smoking and Vaping
Smoking all year round is clearly something the Torah frowns upon because of the damage it causes to one’s health. Nevertheless, one who is smoking regardless need not purchase cigarettes with Passover certification, based on the Mor U’ktzia (Ch. 442) and other great Acharonim.
On the other hand, electronic cigarettes and vapes filled with liquids that may contain Chametz derivatives should be avoided during Pesach without special certification. Although there are those that rule leniently, those who use such products attest to the fact that the liquid has a pleasant flavor when ingested in small amounts and they can feel the taste on their lips. One should therefore refrain from using such products unless one can ascertain that they do not contain any Chametz ingredients.