How to get sneakers white again?

Wash in clothes washer. Yes even leather!

For sneakers I sell on Ebay I use white (not gel) toothpaste and a damp toothbrush. A dab of toothpaste on the toothbrush and gently brush. Wipe with a damp paper towel. Also works on jewelry, porcelain, ceramics, brass,

There is a product called something like Sneaker White. I bought mine in the shoe department at Walmart. You apply it and the canvas whitens as you go. Amazing!

Spray & wash

put a little baking soda and water on a old toothbrush and apply to canvas sneaker

But! I believe my Ex use to put bleach in the washer when washing the kids tennis shoes. Even some of mine. And if it ruined them, I would know about it.

409 and a soft rag

Use white shoe polish.