Nitro-9
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)
An early version for her was homemade gelignite, which more resembled plasticine. She used this to blow up the art room at school, an act for which she was suspended. (TV: Battlefield, Dragonfire)
A 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), a Cyber-shuttle (TV: Silver Nemesis), in a failed attempt to kill Fifi (TV: The Happiness Patrol), and to open 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)