Of all the things you have to remember as a parent, cleaning bath toys is probably not at the top of the list. In fact, if you're like me, you probably didn't even know you had to clean them until, one day, little mildew flakes squirted out when you gave that little duckie a squeeze. Yep. It's gross, and now you're officially wondering how to keep bath toys clean.
According to Real Simple, the first thing you should do is dry off bath toys as soon as bath time is done. This will help to prevent moisture-loving mold from growing in the nooks and crevices of those little toys. Leaving on the exhaust fan also helps, since it'll stop excess humidity from lingering.
Real Simple also noted that if you find your bath toys have already started growing some gunk, you can try a chlorine bleach mixture to get the yuck out. Mix three-quarters cup of bleach into a gallon of warm water and soak all the toys for five minutes. If they're squeeze toys, make sure to suck some of the solution in, shake it around, and squeeze it out (use gloves to protect your hands). Rinse well with hot water, and then air dry thoroughly.
If you prefer a chemical-free option to get things clean, DIY Network suggested using a solution of two cups of white vinegar mixed with five drops of tea tree oil (a natural disinfectant). You can adjust this ratio if you have more or less toys to clean.
The bleach solution might get some of the gunk out, and the vinegar solution is great for regular prevention and maintenance, but neither are a guaranteed cure. After cleaning, if you can still see black mold inside the toy, toss it. They are rubber bath toys, after all, and at some point, they'll get to the point of no return. (Plus, new ones make great stocking stuffers.)