Let (R, m) be a 2-dimensional rational singularity. Assume that R is a Muhly domain: (R, m) is an integrally closed Noetherian local domain with algebraically closed residue field R/m and the associated graded ring gr m R is an integrally closed domain. Let I be a complete m-primary ideal of R and let v 1 , . . . , v n be the Rees valuations of I . For every v i = ord R , there is a complete m-primary ideal I i of R such that I i is quasi-one-fibered (i.e. I i has exactly one Rees valuation different from ord R ) and the degree coefficient of I i with respect to v i is d(I i , v i ) = 1. We show the following formula: Im s = I u 1 1 . . . I u n n for some s, u 1 , . . . , u n 0. We then prove that if ord R is not a Rees valuation of I and if gcd(u 1 , . . . , u n ) = 1, then I is projectively full.