Thanks Steve! 
Tape is great for square contact like a m&t, but I hate it when time to remove all the bits of tape that tear off and leave pickings around the joint.
With wax, I'll just dry-assemble the joint and use a Q-Tip to work into the corners. Some wax does bleed into the joint area but rarely does this encroach significantly into the joints glue area.

Removing the wax is far easier then removing glue from the raw wood!