When ever i go to poop in washroom and use water to make my self paak, i always end up making my other body parts najis because of najis water as per law. I have read that cloth also can be used to make anus paak. I read the law but did not get it about how to use cloth to make anus paak. can u please explain the total method?

Ayatullah sistani ke fatwe ke hisab se kapda mitti se bhi paak ho jaega shart ye haiki bilkul saaf hojae, Haan agar had se zyada area ganda hai ya bahar ki najasat jaise khoon laga hai to wo paak na hoga, kapde me behtar hai 3 baar saaf karen