It was a handkerchief. He used it later in the debate. The guy has plenty of legitimate shady dealings, we don't need to stoop to their level by assuming conspiracies when none exist.
It looked suspicious at the beginning, then they came out with an explanation, plus a clip from later in the debate when he picked up the handkerchief to use it. That's good enough for me to admit I was initially mistaken and drop the issue.