Handles on my white refridgerator have yellowed how can I get them white again?

You may have to replace the handles to get them truly white again.

Do you have gas heat? If so, that is probably what caused the yellowing. Short of repainting with appliance paint you will probably have to replace them.

If using bleach has not worked, then a replacement is in order.

There is homemade concoction for plastic computer cases called retr0bright.
http://retr0bright.wikispaces.com/

But @john65pennington is right, bleach would probably have worked if it is possible.

Sometimes bleach can actually turn plastic yellow, or so the appliance guy told me. I have the same problem with the oven handle on my stove.

@jaytkay I have yellowing refridgerator handles and some old computer cabinets and hydrogen preoxide. All I need is a UV light and dome Oxiclean to test out the recipe. Thanks

a paste of hydrogen peroxide and baking soda left sitting for a few minutes worked on my stove handles.