Which component is a characteristic of non-setting masks?

Non-setting masks are characterized by their composition, which typically includes oils and emollients. These ingredients work to hydrate and nourish the skin without drying or hardening during the application process. This characteristic makes non-setting masks particularly suitable for clients with dry or sensitive skin, as they provide moisture and can help to improve the skin's texture and appearance without creating a tight or uncomfortable feel.

Oils and emollients in these masks create a barrier that helps to lock in moisture and can deliver beneficial nutrients directly to the skin. They are designed to be left on the skin for a period of time while providing a soothing experience, after which they can be easily removed without the need for any setting or hardening.

The other components listed do not inherently define non-setting masks. For instance, clay-based ingredients, such as Helena clay, are typically found in setting or drying masks, which work to draw impurities from the skin. Charcoal particles are also often used in masks meant to detoxify and clarify the skin, but these usually have a setting effect. Sugar crystals, while utilized in certain scrubs or exfoliants, do not fit the profile of components typically associated with non-setting masks.