Cov lim dej muaj cov haujlwm tseem ceeb hauv qab no:
1. Lim: Cov lim dej zoo tshem tawm cov impurities ntawm huab cua, dej, thiab lwm yam ntaub ntawv.
2. Kev cais tawm: Cov lim cais cov khoom tsis zoo xws li cov kab mob thiab cov kab mob los ntawm huab cua thiab dej.
3. Kev Tiv Thaiv: Cov lim dej tiv thaiv cov khoom siv thiab cov khoom tom qab los ntawm kev sib kis thiab kev puas tsuaj.
4. Purification: Lim txhim kho cov khoom purity thiab zoo.