תערובת חמץ עוברים עליו משום בל יראה ובל ימצא כגון המורייס וכותח הבבלי ושכר המדי וכל כיוצא באלו מדברים הנאכלים אבל דבר שיש בו תערובות חמץ ואינו ראוי לאכילה מותר לקיימו בפסח כגון עריבת העבדנין שנתן לתוכו קמח ועורות אפי' נתנן שעה אחת קודם הביעור ה"ז מותר לקיימו ואם לא נתן העורות ונתן הקמח קודם ג' ימים לשעת הביעור מותר לקיימו שהרי נפסד והבאיש תוך ג' ימים חייב לבער וכן הקילור והרטיה והאספלנית והתריאק"ה שנתן לתוכן חמץ מותר לקיימן בפסח שהרי נפסד צורת החמץ:

The law of mixtures containing ḥametz, consisting of 11 סעיפים: A mixture containing ḥametz is subject to the prohibitions of “it shall not be seen nor found”, such as muryas, Babylonian kutach, Median beer, and similar items that are edible. However, anything that contains a mixture of ḥametz but is unfit for consumption may be kept during Pesaḥ—for example, a tanners’ vat into which flour and hides were placed: even if they were added one hour before the time of removal, it is permitted to keep it. If the hides were not added, but the flour was placed there three days before the time of removal, it is permitted to keep it, since it has spoiled and become putrid within three days; if it spoiled within three days, one is obligated to remove it. Likewise, eye salves, bandages, medicinal plasters, and theriaca into which ḥametz was mixed may be kept during Pesaḥ, since the form of the ḥametz has deteriorated.

Bread itself that has become moldy and unfit even for a dog’s consumption, or a medicinal paste that has spoiled, does not require removal.

Garments that were washed with wheat starch, and papers that were glued with ḥametz, and similar items, may be kept during Pesaḥ, since the form of the ḥametz is no longer present. Rema: Therefore, it is permitted to paste papers onto a window within thirty days before Pesaḥ; some are stringent if it is visible from the outside.

Anything into which ḥametz was mixed but is not food for humans at all, or not food for everyone—such as theriaca and the like—even though it may be kept, is forbidden to eat until after Pesaḥ; even if it contains only the slightest amount of ḥametz, it is forbidden to eat. Rema: Later (Siman 447:4) it will be explained that some disagree and permit it if it was nullified before Pesaḥ, and this is the accepted ruling.

Beer made from wheat or barley must be removed; likewise, if cheeses were set using vinegar made from barley or wheat beer, they must be removed.

It is customary to scrape the walls and chairs that came into contact with ḥametz, and there is basis for this practice; if there is ḥametz in a crack that one cannot reach, one should plaster a bit of clay over it.

Dough found in cracks of a kneading trough: if there is an olive-sized amount (kezayit) in one place, one must remove it; if not, then if it was placed there to strengthen the trough or to seal a hole, it is nullified by its smallness; otherwise, it must be removed.

If there are two half-kezayit amounts in two places with a string of dough between them, we consider: if removing the string would cause them to be taken together, one must remove them; otherwise, one need not. This applies to a trough; however, in a house, even if removing the string would not take them together, one must remove them, because sometimes one gathers them. If there is half a kezayit in the house and half a kezayit in the upper story, or half in the house and half in a portico, or half in one house and half in an inner house—since these halves are attached to walls, beams, or floors, one is not obligated to remove them, but nullifies them in his heart and that suffices.

Ḥametz that became moldy before its prohibition time and became unfit for a dog’s consumption, or that was burned (before its time) and charred until it is unfit for a dog, or that was designated for sitting and plastered with clay—may be kept during Pesaḥ.

Ink that was cooked with barley beer is permitted for writing.

Kneading troughs in which ḥametz dough is kneaded—one should not rely on washing them with hot water and scraping out the ḥametz, because it is impossible to clean them so that a total of a kezayit does not remain, and the vessel combines it; therefore, one must give them as a gift to a non-Jew until after Pesaḥ or plaster them with clay. The same applies to dough in wooden vessels that cannot be removed. Rema: It is good to do this for all vessels in which flour is kept throughout the year (Mahariv), and likewise for vessels in which bread is kept all year; and a cloth that was placed on a sack of flour—shaking it is not sufficient, and it requires washing in order to use it during Pesaḥ (Maharil).