Let R be an associative ring with identity 1 6= 0. An element a ∈ R is called clean if a = e + u with e an idempotent and u a unit of R and a is called strongly clean if, in addition, eu = ue. A ring R is called clean if every element of R is clean and R is strongly clean if every element of R is strongly clean. When is a matrix ring over a strongly clean ring strongly clean? Does a strongly clean ring have stable range one? For these open questions, we prove that Mn(C(X)) is strongly π-regular (hence, strongly clean) where C(X) is the ring of all real valued continuous functions on X with X a P-space; C(X) is clean iff it has stable range one; and a unital C∗-algebra in which every element is self-adjoint is clean iff it has stable range one. The criteria for the rings of continuous complex valued functions C(X, C) to be strongly clean is given.