Shekalim, Chapter Four, Mishnah Eight
This mishnah deals with a person who dedicated his belongings to the Temple and there were among them things which could be offered on the altar, but they were not animal sacrifices, as was the case in mishnah 7.
One who dedicated his possessions to the Temple and there were among them things fit for the altar, [such as] wines, oils, and birds:
Rabbi Elazar says: they should be sold for the use of [offerings of] each particular kind, and they should bring with the proceeds burnt offerings, and the other possessions should go to the repair of the Temple.
Rabbi Elazar says that the wines, oils and birds should be sold to people who need to bring wines for libations, oils to accompany minhah (grain) offerings or various bird offerings. The proceeds from the sale should be used to buy burnt offerings, and then, as is standard, all of the other dedicated possessions should go to the upkeep of the Temple.
The Rambam explains how this situation differs from the situation in mishnah seven, where Rabbi Eliezer said that animals dedicated to the Temple should be sold to people who need them for sacrifices and the proceeds go to the repair of the Temple. That mishnah discussed animals and not wines, oils and birds as does our mishnah. Animals dedicated as sacrifices can be, under certain circumstances, redeemed. If the animal becomes blemished, it is redeemed with money and the money becomes sacred and is used to buy another sacrifice. Since the money becomes sacred, when these animals are sold it is as if the mitzvah has been already performed and the money can be used for the repair of the Temple. In contrast, wine, oil and birds cannot be redeemed with money. Therefore, when they are sold the money itself does not become holy. Since the money is not holy, the mitzvah has not been performed and therefore the money must be used to buy burnt offerings, through which the mitzvah can be performed.