What is the obligatory amount to wash from the marital bed after intercourse?

If nothing has soiled the bedding, there is no need to wash it. If semen (maniyy) has soiled it, it should be washed for cleanliness and recommendation, not out of obligation; because semen is pure according to the preponderant opinion. If prostatic fluid (madhiy) has soiled it, then the part it soiled must be washed out of obligation; because prostatic fluid is impure. Purifying the impurity of the bedding is not obligatory unless one prays on it; otherwise, it is merely recommended.