Tim is quite correct, and it is for the end user to certify all empty cartridge cases and packaging is free from explosives, ie, live ammunition, booster charges, CS gas pellets etc etc.
When I was serving I always did it myself, ie check containers and sign off the certs. Army was pretty strict, and a good friend lost his LSGC medal for trusting a J/NCO with the job, resulting in an unused 25 pdr booster charge being left in a box and subsequently found resulting in a disciplinary. He did regain it after some time, but it made him wary in the future.
Alan1.