Q: When the Monstrance is placed on the altar for adoration should a corporal be placed under the Monstrance? Should the cope-like covering remain on the monstrance on the altar until the lunette is inserted?
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A: There is no reference to the corporal, so I believe it is not proper to use one, but you’ll find people who disagree with me. The corporal’s primary usage is connected to the liturgy of the eucharist at mass. It is removed as part of the elements of the purification of vessels.
If exposition follows mass, the monstrance is placed “on the altar” (Holy Communion and Worship of the Eucharist Outside Mass 94). Otherwise it is placed on the altar top, which is covered with a cloth, not a corporal (93).
There is no reference to the cope-like covering of a monstrance. If such a cloth is used to protect it from dust in the sacristy, it should be removed before bringing the monstrance to the altar.