To remove mildew spots from an inflatable, such as a bouncy castle, follow these steps:

1 Safety Precautions: Work in a well-ventilated area and wear gloves and a mask to protect yourself from potential allergens or irritants.

2 Cleaning Solution: Prepare a cleaning solution by mixing equal parts of water and white vinegar. Vinegar is effective at killing mildew and mold and is generally safe for cleaning inflatables.

3 Test in a Small Area: Before applying the cleaning solution to the entire mildew-affected area, test it in a small, inconspicuous spot on the inflatable to ensure it does not cause any discoloration or damage.

4 Scrubbing: Dip a soft-bristled brush or sponge into the cleaning solution and gently scrub the mildew spots. Be careful not to use excessive force that could damage the inflatable's material.

5 Rinse: After scrubbing, rinse the cleaned area with clean water to remove the cleaning solution and any remaining mildew.

6 Drying: Allow the inflatable to dry completely before storing or using it again. Ensure it is completely dry to prevent further mold or mildew growth.

7 Sunlight: If possible, expose the inflatable to direct sunlight for a few hours. Sunlight can help kill remaining mildew and prevent its regrowth.

8 Preventive Measures: To avoid mildew from returning, store the inflatable in a dry, well-ventilated area when not in use. Avoid storing it while it is still damp or wet.

9 Regular Cleaning: Perform regular maintenance and cleaning of the inflatable to prevent mildew growth in the future.

If the mildew spots are extensive or stubborn, you may consider using a specialized mildew cleaner that is safe for use on inflatables. Always read and follow the manufacturer's instructions when using any cleaning product.

Remember, prevention is key to maintaining the cleanliness and longevity of your inflatable. Regularly inspect and clean the inflatable, and store it properly to minimize the chances of mildew or mold development.