As mentioned, we are nearing the end of Zevachim in the daf yomi. The last two chapters, 13 and 14, deal with the prohibition of bringing sacrifices outside of the Temple, even if they are brought to God. The first mishna in the beginning of the 14th perek (112a), opens with two exceptions: the seir ha' mishtalayach, the goat sent over the cliff on Yom Kippur, and the parah Adumah, the red heifer which was slaughtered and burned outside the Temple, and whose ashes were used to make the mei chatat, the ritual water that would purify those who had become tamei due to contact with a corpse. The reason that one is exempt for sacrificing these outside of the Temple is because the were never intended to be brought in the Temple regardless, they are not "ra'oy li'petach ohel moed," fit, or intended, for sacrifice in the Temple. Thus, the subversion of their purpose or of their kedusha is less severe than it is in the case of classic sacrifices offered on private altars.
These two (pseudo-)sacrifices which are intended to be brought outside the Temple, can serve as helpful models in understanding another phenomenon - the parim v'seirim ha'nisrafim - the cows and goats which are burnt outside the Tempe and outside of Jerusalem. These are all chataot, sin offerings, and consist of the (1) the two cow chataot in Vayikra 4:1-21, the chatat brought when the Kohen Gadol rules incorrectly and follows his ruling, and the chatat brought when the High Court rules incorrectly and the people follow their ruling; (2) The Kohen Gadol's cow brought on Yom Kippur for his sins and the goat brought on Yom Kippur for the sins of the people (besides the goat that is sent over the cliff) [Vayikra 16:1-34]; and (3) The goats brought when the people have all committed the sin of idolatry [Bamidbar 15:22-26].
As can be seen by this list, they are all sins of large proportions - either of leaders, of the community as a whole, or of idolatry. The Torah commands that the blood of these sacrifices be brought into the heichal, the inner sanctum, and sprinkled on the curtain that divides it from the kodesh kodashim, the holy of holies, and on the gold altar of incense. Clearly, the sin requires special atonement, and one must get even closer to God's presence to effect the atonement. Alternatively, the Torah describes, particularly in the section dealing with the Yom Kippur sacrifices, that the effect of sin is that it impurifies the Sanctuary, the Temple. The greater the sin, the more it contaminates, and enters into an even holier space - the inner sanctum. Thus, this needs to be cleansed and purified, and that is the function of these parim v'sei'irim ha'nisrafim.
While this is what is done with the blood, the meat is treated in quite the opposite manner. It is taken out of the Mikdash, out of the camps that surround it - in Israel, this would mean out of Jerusalem, the city that surrounds it, and burnt into ashes. Presumably, this is reflecting the dual nature of this chatat. It needs to go into the innermost sanctum to do its work, but this closeness is coming, in necessary, at a time of greater distance, great sin and tumah. Thus, while the blood can, and needs to, go into the heichal, the meat cannot be treated as a normal sacrifice. It is inappropriate for it to be "consumed" either by the Kohanim or by the altar. Perhaps it would even be proper to say that the severe tumah, impurity, that needed to be cleansed, left the Sanctuary and adhered, to some degree, to the meat of the sacrifice. Unlike normal sins which disappear upon the act of sacrificial atonement, these sins do not go away so easily. Even when the cleansing is done, like tough stains, they do not come out so quickly. They attach to the meat, and thus the meat must be taken out of the Sanctuary, out of all the camps, and burnt and destroyed.
The meat, then, according to this explanation, serves somewhat of a "scapegoat" function, like the Seir laAzazel, the goat on Yom Kippur that is pushed off the cliff. That goat, too, is sent out of all three camps, so that it can "carry the sins of the Children of Israel into the wasteland." The sin, in its metaphysical expression of tumah, is, in both cases, carried out of the camp, and destroyed. This also explains another parallel between the two categories - to wit: that both those who take out the Seir La'azazel and those who burn these cows and goats, become tamei in the process. In fact, our Mishna teaches that according to the majority opinion not only does the one who burns these cows and goats become tamei but even those who are involved in taking them out of the Mikdash and bringing them outside the camp, just like with the Seir La'azazel. While one could perhaps conceptualize this as part of being involved in the act of burning (as this is a necessary prerequisite), the Gemara see to say otherwise. The Gemara (105b) makes clear that it is learned from the separate verse and separate verb that says, "And it shall be taken outside the camp," (Vayikra 16:27), and the braitta (105a) lists the act of taking them out separately from the act of burning them. In short, the tumah adheres to those who are mitaskim bo, "involved with it, (105a). Because the tumah has attached itself to the meat, it will attach itself to anyone who is involved with it.
R. Shimon in the mishna disagrees with all of this, and states that only those who burn these cows become impure. He, apparently, does associate it with the Seir Lazazel, and sees this perhaps as more of a ritual and less of a destroying of the carrier of tumah. There are two other positions of his which correspond to this understanding. The Gemara (105b) states that he would agree with the position of R. Eliezer that these cows and goats are burnt in the same place that the parah adumah, the red heifer, is burnt, to the east of Jerusalem. This seems to identify the burning as a ritual, like it is with the parah adumah, the other sacrifice brought outside the Temple, and as a ritual it is not intended as a destructive act.
In the case of the parah adumah, the slaughtering and sprinkling of the blood is not done in the Mikdash, but in a place to the east of Jerusalem, facing the Sanctuary. The blood is sprinkled towards the opening of the sanctuary, thus making this a sacrificial act that takes place outside the Sanctuary but in connection to it. It would seem, According to R. Shimon, that the same is true for the burning of the parim vi'seirim ha'nisrafim. They are burnt just like the olah is burnt on the mizbayach, the altar, as part of the sacrificial act. Here, the sacrificial burning is not on the altar, but on this extension of the Mikdash, this site that is to the east of Jerusalem and facing the Mikdash. It is, nevertheless, a ritual sacrificial act.
In a similar vein, we find a debate at the very end of the chapter regarding how much the meat has to be burnt. According to R. Shimon, the position quoted in the Mishna, the meat only has to be burnt until it becomes charcoal, i.e., is no longer meat. According to the Rabbis, however, it must be burnt until it becomes completely ashes. If the goal is a ritual act of burning, then making it charcoal is enough, it is na'asit mitzvato, its mitzvah was performed. However, if the goal is to destroy it, then it must be completely destroyed. [In the case of the parah adumah, however, it must be ashes to be mixed with the water afterwards, and thus for a different reason it is not complete until it becomes ashes.]
The one seeming anomaly this understanding is the Gemara's statement (106a) that according to the Rabbis the cows and goats would be burnt in the north. This, presumably, is because in the Sanctuary a chatat is brought in the north (so Rashi, ad. loc.) This would seem to see the burning as a ritual, sacrificial act. However, we may note that the act of burning - as opposed to slaughtering - is never associated in the Sanctuary itself with the north. More significantly, Rambam seems to understand that this is not the halakha, as he does not bring down any requirements for the location of the place of burning other than it being outside of Jerusalem (Acts of Sacrifices, 7:3). It seems according to him that this is an act of destruction, not some sacrificial ritual, and can be done anywhere outside of Jerusalem, the extended Temple precincts.
It thus seems that we have two models to which to compare these parim ha'nisrafim - the Seir La'azazel and the parah adumah. The first is a scapegoat, which we are casting out and destroying. The second is a sacrifice, whose ritual is done out of the Temple. The Rabbis understand these cows and goats to be a form of the first, whereas R. Shimon understands them to be a form of the second. We ultimately side with the Rabbis, a position which is consistent with the description of the cleansing of the Mikdash from tumah on Yom Kippur, and makes the cow and goat of Yom Kippur of a piece with the Seir Lazazel of that day.
[This was adapted from my blog post on the Daily Daf]