Hilchos Maasei Hakarbanos 8:5

If the blood splattered onto fish skin, it need not be washed because fish skin isn’t susceptible to ritual uncleanliness. If it splattered onto the hide of an unskinned animal, it likewise need not be washed, but if the hide was removed from the animal then it must be washed. This is because, even though it is not yet subject to ritual uncleanliness as it is, it will be once it has been processed.

Hilchos Maasei Hakarbanos 8:6

If blood splattered from the animal’s neck onto a garment, it if ran from the corner of the altar onto a garment, or if it spilled onto the floor of courtyard from where it was collected and then it spilled onto a garment, the garment need not be washed. This is as per Leviticus 6:20: “If its blood is sprinkled,” limiting the requirement to blood that was received in a service vessel, that may be sprinkled on the altar, and is of sufficient volume to be sprinkled.