Trying to explain incense to children of a minimalist parish...

.... whose only encounters with its fragrances are likely through the hippie-slash-beachcomber denizens of this area?
Not easy.
And myrrh?
Eeeeeeeeeeew, you mean they were going to touch His body???!?!??$?%????!?!?!!? (I employed the upper case for the pronoun, it was almost certainly not inherent in the line reading of the little heathen who asked the question.)
Nearly hopeless.
This, by Peter Leithart caught my eye:

JPM Sweet points out that the Greek word “Smyrna” means myrrh, the perfume given to Jesus by the magi and, importantly, part of the mix of spices used for Jesus’ burial (John 19:29). Jesus... now sends a message to the church of myrrh,. which is also facing death but promised resurrection.

Myrrh was a component of the holy anointing oil for the priests (Exodus 30:23), and was one of the perfumes that created an aromatic cloud around the king (Song of Songs 3:6) and grew in the garden that was the bride (Song of Songs 4:14). With a church at Smyrna, Jesus is the myrrh-anointed Priest, the holy Lover, and the suffering church is also a priest in Him, the perfumed beloved.

Of course, the notion that what happens in the Smyrna where Christianity is in such danger might be of any interest to them, when there is another Smyrna just a hop and skip from Disney World would be an even harder sell than the value of myrrh....