A piece that absorbed a prohibition without 60 against it, then falls into a pot, forbids only in proportion to the prohibition it contains (לפי חשבון): if the pot + the piece total 60 against the absorbed prohibition, the rest is permitted — but the piece itself remains forbidden (אפשר לסוחטו אסור). The distinction liquid (נבלל ונימוח) / solid (יבש), and by our custom חתיכה נעשית נבילה for all prohibitions; plus the practical conduct for removing a piece from a pot (Shulchan Aruch, Yoreh De'ah 106 — 2 se'ifim)
חֲתִיכָה שֶׁבָּלְעָה אִסּוּר וְאֵין בָּהּ שִׁשִּׁים לְבַטְּלוֹ, שֶׁנָּפְלָה לִקְדֵרָה — אֵינָהּ אוֹסֶרֶת אֶלָּא לְפִי חֶשְׁבּוֹן אִסּוּר שֶׁבָּהּ. שֶׁאִם יֵשׁ בְּמַה שֶּׁבַּקְּדֵרָה, מְצֹרָף עִם הַחֲתִיכָה עַצְמָהּ, שִׁשִּׁים כְּנֶגֶד אִסּוּר הַבָּלוּעַ בָּהּ — מֻתָּר מַה שֶּׁבַּקְּדֵרָה. אֲבָל הַחֲתִיכָה עַצְמָהּ אֲסוּרָה, לְפִי שֶׁאִסּוּר שֶׁבָּהּ אֵינוֹ נִפְלָט מִמֶּנָּה לְגַמְרֵי.
A piece that absorbed a prohibition and does not have sixty to nullify it, and which fell into a pot, forbids only in proportion to the prohibition it contains: if what is in the pot, joined to the piece itself, totals sixty against the prohibition absorbed in it, what is in the pot is permitted. But the piece itself is forbidden, because the prohibition in it does not fully leave it.
Shulchan Aruch, Yoreh De'ah 106:1LEVEL 01
Hebrew text of the 2 se'ifim with a fluent English translation. Proportional reckoning (לפי חשבון), the piece that remains forbidden (אפשר לסוחטו אסור), the distinction between liquid and solid (נבלל ונימוח / יבש), and the practical conduct for removing a piece from a pot explained with practical cases.
📖 StudyLEVEL 02
In-depth pilpul: the sugya of the כחל (Chullin 100), the question of the Tur according to the Taz, the yesod of אפשר לסוחטו אסור limited to בשר בחלב, the great מחלוקת חתיכה נעשית נבילה between the מחבר (לפי חשבון) and the Rama (חנ״נ in all prohibitions, see סימן צ״ב), חקירות and נפקא מינות.
📖 StudyLEVEL 03
Comparative tables (לפי חשבון Mechaber / חנ״נ Rama, liquid נבלל ונימוח / solid יבש, piece recognized or not), golden rules, classic pitfalls (אפשר לסוחטו אסור, חתיכה הראויה להתכבד) and memorization of the 2 se'ifim.
📖 StudyLEVEL 04
The practical halacha according to the Shach, Taz, Pri Megadim and Pitchei Teshuva (Noda BiYhuda, Tiferet Tzvi), then the Sephardic poskim (Yabia Omer, Yalkut Yosef, Or LeTzion) and Ashkenazi poskim — the Sephardic (לפי חשבון) / Ashkenazi (חנ״נ, 60 against the whole piece) divergence. Note: the Shulchan Aruch HaRav does not deal with this siman — this is a level of psak, not "Daat HaRav".
📖 StudyA piece that absorbed a prohibition without having 60 to nullify it, then falls into a pot, forbids not according to its whole volume but only in proportion to the prohibition it contains (לפי חשבון איסור שבה). One therefore counts 60 against the absorbed prohibition, and the piece itself joins the count: if what is in the pot, joined to the piece, totals 60 against that prohibition, what is in the pot is permitted. For practical halacha, consult your Rav.
Because the absorbed prohibition does not fully leave the piece (אינו נפלט ממנה לגמרי): what one could press out of it remains forbidden (אפשר לסוחטו אסור). Even when the rest of the pot is permitted thanks to the 60, the piece itself remains forbidden. This differs from a liquid that mixes and dissolves (נבלל ונימוח): if blood falls into permitted juice and forbids it, then the permitted increases up to 60, all is permitted, for the whole is dissolved. For practical halacha, consult your Rav.
A piece that contains chelev, cooked in a pot that has 60 to nullify it: one must not remove anything from the pot while the forbidden piece is still in it (lest it be the last to remain, when there is no longer 60), nor take it out first (the chelev in it would forbid it). The remedy is to let the pot cool. According to our principle חתיכה נעשית נבילה (Rama), one simply removes the forbidden piece and the rest is permitted. For practical halacha, consult your Rav.