When the white vinyl covering of your refrigerator handle turns yellow, the cause is often a buildup of common kitchen grease and dirt. If that's the case, you can restore the color by scrubbing with mild abrasives and gentle cleaners. You should avoid harsh cleaners, such as ammonia, because these can damage the vinyl. If your refrigerator is in a kitchen that gets a lot of bright sunlight, the yellow may be because of ultraviolet degradation of the plastic. If that's the case, you won't be able to clean it, but you can give it a coat of paint to restore the color.
Moisten a non-abrasive cleaning pad with water; then sprinkle baking soda on it and rub down the handle. Rinse the handle with clear water; check your progress and repeat with a fresh supply of baking soda, if necessary.
Wring out the cleaning pad, dip it in white vinegar, and then add baking soda, if stronger cleaning is necessary. Rub in a circular motion. Leave the cleaning solution on the handle and scrub with a toothbrush if you need more cleaning power. The toothbrush is especially effective for removing grime from textured vinyl.
Depending on the handle style, remove it by unscrewing it from the door with a screwdriver if you can't lift it off. Clean it in the sink, using dish detergent and water or baking soda and vinegar.
Spray the handle with white appliance enamel if you can't restore the white color by scrubbing. Remove the handle and take it outside to do this, and wear a respirator. Let the paint dry overnight before reattaching the handle to the refrigerator.