Du'a for purification from sins

اللَّهُمَّ بَاعِدْ بَيْنِي وَبَيْنَ خَطَايَايَ كَمَا بَاعَدْتَ بَيْنَ الْمَشْرِقِ وَالْمَغْرِبِ، اللَّهُمَّ اغْسِلْنِي مِنْ خَطَايَايَ بِالْمَاءِ وَالثَّلْجِ وَالْبَرَدِ

Allahumma ba'id bayni wa bayna khatayaya kama ba'adta baynal-mashriqi wal-maghrib, allahummaghsilni min khatayaya bil-ma'i wath-thalji wal-barad

O Allah, separate me from my sins as You have separated the East from the West. O Allah, wash away my sins with water, snow, and hail.

Ṣaḥīḥ al-Bukhārī 744