Handling the remains of sacred sacrifices that have fulfilled their holy purpose brings about a unique requirement for personal purification. The very act of dealing with these remnants of holiness imparts ritual impurity to the individuals involved [ביאור שטיינזלץ]. This state of impurity takes effect the moment those carrying the sacrifices step outside the boundaries of the Divine camp [פירושי רד צ הופמן].
A precise distinction is made regarding who exactly contracts this impurity. The primary approach among commentators is that the impurity falls exclusively on those who actively engage and assist in the physical burning of the sacrifices. If multiple people participate directly in this task, all of them become impure [ביאור יש״ר]. However, an individual who merely arranges the wood or sparks the initial flame remains pure. The impurity is tied strictly to the human action of causing the sacrifices themselves to burn, rather than the preliminary steps of setting up the fire [מלבי״ם, פרדס יוסף, אילת השחר, תורה תמימה].
There is also a strict time limit on when this impurity applies. A person is affected only while actively burning the physical bodies of the sacrifices. The moment the meat breaks down and is reduced to ash, the process is considered complete. From that point forward, handling the remaining ash no longer transfers impurity to the person or their clothing [תורה תמימה, מלבי״ם, אדרת אליהו].
To restore a state of purity, the individual who performed the burning must fully immerse their body in a ritual bath. After this immersion, they must wait until the sun sets before they are permitted to return to the camp, which refers to the Temple courtyard. Some maintain an even stricter boundary, suggesting that the individual is completely barred from entering the city limits of Jerusalem until the entire purification process is finished. This severe distance serves a profound purpose, emphasizing the heavy weight of the sins and wrongs that these specific sacrifices carried away [רלב״ג].