My main reference is to impurity without trace of sight or smell, but please give the ruling also if you can see the dry impurity. I do not mean the impurity is on your body or clothes, I mean if you pass it and it rubs your body or clothes-are you still 100% pure for Prayer.
Answer
An impurity like stools, etc. doesn’t become pure by drying, however once it dries then for it to make something else impure, the condition would be for its effect (taste, smell or colour) to become apparent on this other item. (Imdaadul Fattah Pg.161-162)
And Alah Ta’ala knows best
Mufti Ebrahim Desai