You’ve got to get rid of that body in the garage somehow.

This ritual requires:
One corpse,
A deep-freeze or large freezer (or very cold weather and a privacy fence)
A saw, preferably a power saw,
A number of ziplock bags,
A number of coolers,
Ice,
…and an idea of the whereabouts of the area’s hotels and motels.

‘All the trustworthy friends you have,’ are optional, but very, very, helpful.

The corpse, as a whole (or in the pieces its cause of death divided it into) is to be frozen before being cut into pieces; these pieces may vary however you’d like in size, but must remain frozen throughout the ritual, as the ritual fails if any piece thaws.

Take these pieces, packed away in ice, into a hotel; you must pass through the main entrance. The person most responsible for the fact of the body must rent a room, and any friends helping must wait for them to do so. Afterwards, a systematic tour of the hotel must be made, with a stop at any ice machine. That most responsible person is to hide the body parts inside these machines, one piece in each. (I hope you cut them small enough to bury in the ice.)

If anyone sees you hide a piece, or discovers a piece while you’re hiding other pieces, the ritual fails. Friends guarding machines are godsends, but the ritual will fail if even they watch a piece being placed.

Note: If you have more parts than machines, you’ve got to travel to the nearest hotel of the same chain and use its ice machines to hide the remaining pieces. Again, go in and out through the main entrance.

After all the pieces are hidden, walk to the front entrance, and leave the building. It is at this point charges (if the GM assigns any) must be spent, or the ritual is complete (if it is being powered by your sheer and utter nerve). Granted, the walk from the last machine to the door leaves a window of time open for a discovery, but it’s a small risk in the face of everything else.

If the ritual is a success, body parts vanish as you cross the threshold, with no trace left on or in the ice. (Of course, you’ll still have to clean up any bloodstains at home.) While this is magic, that mass still should be going somewhere; most hotels have a convenient connected restaurant, and some suitable freezer. Ground meat is inconspicuous, and it’s unlikely any one person will notice what appears in there on its own.