Zevachim 92 - Washing Garments in the Courtyard
The Torah says that the blood of a sin-offering has special laws , because it cannot leave the Courtyard. Thus, if its blood spattered on a priestly garment, that garment must be laundered in water right in the Courtyard. If the offering was cooked in a earthenware vessel, the vessel must be shattered, and if it was a metal vessel, it must be purged. Also, any food that touches the meat of a sin-offering and absorbs its flavor assumes the same stringencies as the meat.
Thus, the rule is that if blood of a sin offering is spattered on a garment, this garment requires laundering in the Courtyard. Even though the Torah, in giving this law, spoke only about sacrifices that are eaten, the law is equally applicable to other sin-offerings, which are not eaten, but are brought in the Holy of Holies instead. Nevertheless, the stringency of laundering in the Courtard only applies to valid blood, but if the sacrifice was invalidated, laundering can be done elsewhere, whether the offering had a period of time when it was valid, or if it was never valid.
Art: Camille Pissarro - Woman Hanging up the Washing