Nitro-9 was a powerful explosive created by Ace: "just like ordinary nitroglycerin, except it's got a bit more wallop". Ace mixed it herself, and put it inside deodorant cans. (TV: Dragonfire) Once activated, it had a fuse time of 8 seconds, though sometimes it was not too precise as the Seventh Doctor discovered. (TV: Remembrance of the Daleks)

An early version for her was homemade gelignite, which more resembled plasticine. She used this to blow up the art room at her secondary school, an act for which she was suspended. (TV: Battlefield, Dragonfire)

A later variant of Nitro-9 was Nitro-9a, which was half the size and half as powerful. (PROSE: Timewyrm: Exodus) Another variant of Nitro-9 was Neo-Nitro, which resembled boiled sweets and was activated using saliva. (PROSE: Shadowmind) Ace also created Nitro-9 smart bombs, which could fly and take verbal commands. (PROSE: Blood Heat)

Though the Seventh Doctor told Ace not to carry it, she continued to do so and used it to destroy a Renegade Dalek, (TV: Remembrance of the Daleks) in a failed attempt to kill Fifi, (TV: The Happiness Patrol) to blow up a Cyber-shuttle (TV: Silver Nemesis) and to excavate the entrance to King Arthur's spaceship. (TV: Battlefield) However, he asked her to use it against sentient mud walls who where trapping them in a pocket dimension. (AUDIO: The Light at the End)

After Irving Braxiatel had returned her from the Last Great Time War (AUDIO: Soldier Obscura) Ace used a couple of rusty cans of Nitro-9 plus gas from the chemistry lab at Coal Hill School to try to blow up a Dalek. (AUDIO: In Remembrance)