If the inner garments contained prostatic fluid (madhy) and the outer garments were then changed, do the outer garments become impure?

If the madhiy (pre-seminal fluid) is dry, it does not nullify the purity of any dry outer clothing it touches. However, if it is wet, it does nullify the purity of the clothing it touches, provided that the madhiy actually makes contact with the clothing. This is also a warning against obsessive doubts (waswasah).