When plastic is exposed to light or oils for an extended period of time, a chemical reaction occurs that causes it to turn yellow. Not to worry — most yellowed-toys can be restored to their original color using bleach and a few items you likely have lying around your house.
Submerge the yellowed item in a bucket filled with equal parts of water and bleach 1.
Wait an hour or longer until the bleach has removed the yellow color. You don't need to do anything else here; just let the toy soak.
Remove the toy from the bucket.
Wash the bleach from the toy using dish detergent.
Dry the toy with a dish towel.
Gently rub superfine sandpaper along any areas that remain yellow 1.
Wipe the toy with a soft cloth to remove any dust from the sanding.
Tips
As an alternative to using bleach, you can scrub the toy with a powdered scouring disinfectant and a moistened scrubbing sponge.