saffron

Hadith question

Q: I ask if the 'Ulama could kindly provide a reference for the following: "There was a Sahaabi (radhiyallahu ‘anh) who had some cracks on his feet and as a form of treatment in that time he applied saffron to the cracks. When Nabi (sallallahu ‘alaihi wasallam) saw this he refused to greet this Sahaabi (radhiyallahu ‘anhu) until he washed it."