the old school napthalene moth balls not the new ones that are made out of a different compound. What he is doing is making an octane booster out of an aromatic compound. these are the types of compounds that are found in race gas in order to increase octane. There are many substances which you can purchase at your local hardware store that have the same effect. Benzene, acetone, methanol.......
these octane boosters work better then the kind in the store, and you can actually calculate your octane increase by using volume percent ratios.