Abu Alaa bin Shukhair narrates from his father: I saw the Prophet (peace be upon him) performing prayer, and during it, he spat nasal mucus under his foot and rubbed it with his shoe which he was wearing on his foot.
Hadith Referenceمسند احمد / مسند المدنيين رضي الله عنهم اجمعين / 16319
Hadith Gradingحکم دارالسلام:حديث صحيح، م: 554، وهذا سند ضعيف لضعف على ابن عاصم، وسماعه من الجريري بعد الاختلاط