Be careful, because they must be nitroglycerin.
And the money quote from the F Troopie In Charge of Spinning the Narrative:
ATF’s Gabe Mamock said the agency couldn’t confirm whether or not the liquid was actually ‘nitro’. “We can’t confirm that,” Mamock said when asked about the identity of the liquid directly. “But, at this time we feel comfortable in saying that I can’t confirm it.”
*pf-f-f-ttt!* Gabe, you owe me a new keyboard.