Former HP CEO Carly Fiorina took a swipe at Hillary Clinton’s grasp of tech issues at the Thursday evening Republican primary debate, mocking her for her responses to questions about her email system.

“We need a president who understands technology in the Oval Office. Mrs. Clinton, actually you cannot wipe a server with a towel,” Fiorina said at the debate, the first of two hosted by Fox Business Network.

The jab was a reference to a comment Clinton made in August, when she casually deflected a question on whether her server had been wiped clean.

“Like, with a cloth or something?” Clinton asked, before maintaining she didn’t understand how it worked “digitally.”

Fiorina suggested it speaks to a broader issue. She said bureaucracies “don’t know how to innovate,” and the government should be asking the private sector for more help on things like improving its databases – in order to find terrorists before they attack the U.S.