Mishnayos Chullin Perek 6 Mishnah 7

With what substances may one cover the blood and with what substances may one not cover the blood? One may cover the blood with fine granulated manure, with fine sand, with lime, with crushed potsherd, and with a brick or the lid of an earthenware barrel that one crushed. But one may not cover the blood with thick manure, nor with thick, clumped sand, nor with a brick or the lid of an earthenware barrel that one did not crush. Neither may one merely turn a vessel over the blood. Rabban Shimon ben Gamliel stated a principle: With regard to a substance in which plants grow, one may cover blood with it; and with regard to a substance in which plants do not grow, one may not cover blood with it.

בַּמֶּה מְכַסִּין, וּבַמָּה אֵין מְכַסִּין. מְכַסִּין בְּזֶבֶל הַדַּק, וּבְחֹל הַדַּק, בְּסִיד, וּבְחַרְסִית, וּבִלְבֵנָה וּבִמְגוּפָה שֶׁכְּתָשָׁן. אֲבָל אֵין מְכַסִּין לֹא בְזֶבֶל הַגַּס, וְלֹא בְחוֹל הַגַּס, וְלֹא בִלְבֵנָה וּמְגוּפָה שֶׁלֹא כְתָשָׁן, וְלֹא יִכְפֶּה עָלָיו אֶת הַכֶּלִי. כְּלָל אָמַר רַבָּן שִׁמְעוֹן בֶּן גַּמְלִיאֵל, דָּבָר שֶׁמְּגַדֵּל בּוֹ צְמָחִין, מְכַסִּין בּוֹ. וְשֶׁאֵינוֹ מְגַדֵּל צְמָחִין, אֵין מְכַסִּין בּוֹ: