Naptha mothballs are increasingly hard to find in the u.s. due to their toxicity.
Paradichlorobenzene (not sure on spelling.) are far more common and far far less toxic- it is the same chemical used for urinal cakes and it is approved for protection of stored honeycombs from wax worms. (Doesn't hurt bees or taint honey if used according to label.

I don't believe either would stop a determined snake, but I can't imagine anyone rubbing themselves with naptha with all the warnings plastered all over the packageing.

Can anyone point me at this train-wrecky sounding video?