What is the difference between toilet cleaning and moth repelling balls?

Dissimilar active ingredients and dissimilar purposes represent the difference between toilet cleaning and moth repelling balls. Cetrimonium bromide tends to be the active ingredient in toilet cleaning balls. It's effective in cleaning and leaving a fresh cleaning smell.

In contrast, the quite toxic naphthaline tends to be the active ingredient in moth repelling balls. It's effective in keeping clothes eating moths away from sweaters and other woollens. Naphthaline has a steady track record that goes back at least to the 19th century in its use as a moth population control. The problem lies in its toxicity. So it's a medical emergency when taken in by humans.