Only some of the exotic ingredients were known that were needed in the process of brewing the Oil of Impact - for example hill giant fingernails and crushed oxen horn. An alchemical device was needed to blend all ingredients together - and a very careful hand to not cause the oil to blow up in the process of brewing.
The oil could be transported in glass vials. Cadderly designed crossbow darts to hold the oil. These darts were small and narrow and made of iron except for silver caps. The centers of the darts were hollowed out to leave room for tiny glass vials filled with the oil. In case those darts impacted on a hard surface (such as a wall, limb of a tree or even an orog's torso) the vial collapsed and the oil exploded.