Tips on keeping a white kitchen white!

Why do those sparkling white cabinets start to yellow? The first culprit is exposure to direct sunlight, which tends to jaundice or fade painted wood (and laminated surfaces). You should consider draperies, blinds or window film to shield your cabinets from direct sunlight. We all have the inevitable muck and grime that accumulate from oil and grease splatters, and food and beverage spills. Do not use abrasive cleansers or scouring pads on painted cabinets, as they can scratch or dull the finish. A soft cotton cloth dampened with warm water is usually sufficient to clean your cabinets looking white. 
If more thorough cleansing is required, use a solution of mild dishwashing liquid mixed with warm water.  Or wash your cupboards with a fizzy mixture of 1 cup vinegar, 2 cups warm water and 1 tablespoon baking soda. To keep cabinets white, give them a monthly “bath” with a solution of warm water and a grease-busting dish soap. After cleaning, wipe all surfaces with a clean, damp cloth. Dry immediately using another soft, clean cloth.
Remember not to let those stains linger. Prolonged exposure to spills can cause permanent discoloration or damage to your cabinets’ finish.
The white sinks in my home take approximately five minutes to look yucky. You can brighten them and remove stains with common household bleach. Experts suggest laying paper towels flat across the bottom of the sink and wetting them with bleach. This prevents the bleach from running straight down the drain. Leave the paper towels in place for half an hour to allow the bleach to do its job, then remove them and rinse the sink thoroughly with warm water. 
For a more natural solution, fill the sink with club soda and lemon juice and let this mixture lift the stains as it soaks in. After you empty the sink, apply straight lemon juice directly to any stubborn stains. You may have to repeat this process several times.