Does impurity transfer to the blanket or bed, or the hand, if there is a spot of prostatic fluid on the outer garment, and one is not certain about the impurity having transferred to them?

If the pre-seminal fluid (madhy) is wet and touches a blanket or anything else, it only defiles the spot of contact. If the exact spot of contamination is uncertain, the entire area must be washed.

If you are unaware of its contact with wet madhy and doubt its contamination, you should sprinkle water on the doubted area. However, if the madhy is dry, it does not defile what it touches, because if a defiled object touches a pure object and both are dry, it does not defile it.

Similarly, the hand or anything else does not become defiled by touching a place near impurity unless it directly touches the impurity, even if it is wet. Impurity only defiles what it directly touches if one of them is wet.