Write-offs, giveaways, and personal use
Boxes leave a shop in more ways than sales: stream giveaways, damaged product, a box you open for yourself, a buyer who never pays. The honest treatment is the same for all of them — a $0 sale. The unit leaves inventory, its full landed cost hits your cost of goods as a realized loss on that date, and the note says why.
Record it as a normal sale: quantity, unit price $0.00, usually no channel, dated when the item actually left your possession, with a note ("stream giveaway", "opened for personal collection", "buyer never paid — written off"). The loss guard will challenge it — that's it working; confirm through.
If you genuinely can't trace where a unit went (a recount comes up short), date the write-off on the day you discovered it rather than inventing history: shrinkage belongs to the period that found it.