It's not recommended to sun-dry smelly cat litter. Not only will it fail to eliminate the odor, but it might actually make the smell worse. Regularly changing the cat litter and cleaning the litter box are the best ways to prevent strong odors.
If your cat's litter smells, it's best to replace it immediately instead of trying to sun-dry it. Exposing the litter to sunlight won’t improve the smell and might even intensify it. Therefore, switching to fresh litter is the best solution for your cat's hygiene.
The odor in your cat’s litter box often comes from a buildup of used litter that hasn't been scooped out, or from infrequent changes of litter. Regular litter changes and cleaning the litter box will help keep odors under control. A clean environment means less unpleasant smells.
If odors persist even after cleaning, it might indicate that the type of cat litter you are using is not very effective at masking the smell of cat waste. Consider switching to a better type of litter. Crystal, tofu, and pine litters are often effective at controlling odors. When purchasing, always buy from reputable stores to avoid low-quality products. For instance, many cat owners use pine litter with good results. Choosing a high quality litter, is key for odor control.