Do you think that nailbrushes improve hand hygiene?
The intended use is to scrub under fingernails to remove outside dirt and potential allergens because no matter how short a person's nails are, it is still difficult to remove any dirt (visible or not) from the nail area.
Each employee would have their own set of nail brushes to use before entering the production area. The nail brushes would be sanitized after each use by soaking in dilute bleach and then washing in the dishwasher (high temperature).
For context the production area is a small bakery producing RTE products and the product is handled after the kill step (baking).