how to clean the RUBBER part of Old Navy Flips flops?

I found that when I used anything to get the rubber part clean, it came out more and more yellow. But since you have nothing to use, you could try throwing them in a tub of bleach - or what I used to clean some of my shoes is put them in a pillow case and tie it up, then throw it in the washer. Helps protect them but cleans them well.

What about a whitening toothpaste? That might work as well. :) I also know someone who cleans all his shoes with an electric toothbrush...he really likes shoes, but I'm sure they're more expensive than Old Navy flip flops. :D

You could try Mr. Clean Magic eraser or you could try Greased Lightening and use an old toothbrush. I have found Greased Lightening can remove things other products can't. You can find it at Walmart in the cleaning supplies area for just a few bucks.

I put my white flip flops in the dishwasher and run it.

Scrub it with comet with bleach

soak them in a solution of oxi-clean and water overnight

bleach