However, we can make some educated guesses:
* High-quality and gentle: Given the Queen's age and the importance of maintaining good skin health, her soap would likely be high-quality and gentle.
* Possibly unscented: As a public figure, she likely uses unscented soap to avoid any strong fragrance that might be off-putting during public appearances.
* Potential for a bespoke blend: It's possible that the Queen has a bespoke blend of soap created specifically for her, tailored to her skin type and preferences.
Ultimately, the specific details of her soap choice remain a royal secret.