Where must all powder used on patrons be kept?

The correct answer is to keep all powder used on patrons in a clean shaker. This practice ensures that the powder remains uncontaminated and hygienic, which is essential for maintaining safety and health standards in any service or beauty environment. Using a clean shaker helps to control the amount of powder dispensed, minimizing the risk of spills and waste while also protecting the product from environmental contaminants.

Moreover, storing powders in a clean shaker as opposed to open containers or on exposed shelves prevents exposure to germs, dust, and other potential contaminants, thereby safeguarding the health of customers. This method aligns with safety protocols that prioritize cleanliness and the use of appropriate tools, which are crucial in industries where personal care products are applied.