Avodah Zarah5: 11
גַּת שֶׁל אֶבֶן שֶׁזִּפְּתָהּ עוֹבֵד כּוֹכָבִים — מְנַגְּבָהּ וְהִיא טְהוֹרָה. וְשֶׁל עֵץ — רַבִּי אוֹמֵר: יְנַגֵּב, וַחֲכָמִים אוֹמְרִים: יִקְלֹף אֶת הַזֶּפֶת. וְשֶׁל חֶרֶס, אַף עַל פִּי שֶׁקָּלַף אֶת הַזֶּפֶת הֲרֵי זוֹ אֲסוּרָה.
A stone winepress which an idolater coated with pitch —- one dries it, and it is cleansed. With a wooden [press] —- Rabbi says: He should dry [it]; but the Sages say: He must peel off the pitch. But an earthen [press], even though he peeled off the pitch, it is forbidden.