Percy was caught between worry and amusement as he realized that by 'something so unimportant' he wasn't sure if Malfoy meant the jewelry box or the auror.
He cleared his throat. "Yes, well. Like most old magic this particular hex runs the risk of being unpredictable. See that care is taken." He rose from his desk, satisfied that he had done the letter of his duty. He couldn't say more than that, since his words were wasted on Malfoy and the hex was no doubt simply an amusement to the man.
Percy didn't hesitate to recover the small jewelry box from a case on a rear bookshelf in the overcrowded office. He didn't hesitate to hold it out to Malfoy, offer the dark magic back to the Death Eater. He had already fought half the aurors in the building over whether such a thing could be returned to Lucius Malfoy, so the moral arguments both for and against it were hollow by then.
"I believe you'll find it in the same condition it left your manor in. If not," he smiled dryly, amusing himself if no one else, "there are forms you can fill out and file with our complaint department."