Our recommendation to fix white cabinets that have yellowed is to do a thorough sanding and precleaning and recoat with the following products:
- Prep clean and scuff sand for adhesion.
- Apply Stain Blocker from GF's line. Many contractors use an oil-based or shellac-based primer.
- Finish sand between coats.
- Apply another coat of durable, cabinet-grade wood coatings paint, not wall paint. From General Finishes line, choose Brushable White Enamel or professional Enduro White Poly.
- Do not apply a topcoat as that can cause yellowing.
This is an industry-wide issue - read this FAQ for more details about the yellowing of white paints: https://generalfinishes.com/faq/how-do-i-prevent-light-colored-paint-yellowing-when-applying-water-based-topcoat and watch this video: http://bit.ly/GFVideoHowToAchieveBrightWhiteFinish