How do I get rid of the white stuff on my cactus?

To remove the white stuff on your cactus, gently wipe it off with a soft cloth or brush. It may be mealybugs or powdery mildew, so you can also try spraying the affected areas with a mixture of water and mild soap or rubbing alcohol. Make sure to keep your cactus in a well-ventilated area and avoid overwatering to prevent further issues.