At least the square root of the total number of export cartons, for first inspections
At least 1.5 times the square root of the total number of export cartons, for re-inspectionsHow to select cartons?
Select cartons randomly, and covering all sizes and colors (if applicable).

Inspector must select export cartons from different parts of the pile of cartons: from the top, from the bottom, from the sides, from the center

If some cartons are hard to reach or hidden (at the back or in the middle of the pile), inspector must select a few of them.
If the cartons are arranged in a way that makes it impossible to reach certain cartons (example: several rows and a wall behind), ask the factory to move the cartons. If they refuse, write a remark in the QC report.
Inspector must double check if the numbers of selected cartons are random enough. If not: replace repeated series numbers by other carton numbers. Example of series: 13, 15, 17, 19.

Transportation of selected cartons to the inspection area
All selected cartons must be chopped by the inspector (except if the outer carton is a gift box). Inspector must record the carton numbers in the report.
The transportation of cartons from storage location to the inspection location must be monitored closely by inspector. Remind the factory to be careful not to damage cartons.

Opening the cartons, and drawing the samples to check
Inspector must open all cartons by himself, or supervise the opening of the cartons. Do not open all cartons at the same time: open 50%, and then 50% later.
In case the inspector has to leave the inspection room temporarily (lunch), he must reseal the opened but un-inspected products.