ᐅ My Kallax is developing yellow stains – what could be the cause?

Hello everyone,

Lately, I have noticed yellow stains appearing on my Kallax shelving unit. These are typical yellow discolorations on the white surface that do not seem to be caused by dirt or similar contamination. The shelves are mainly used in a relatively dry room with normal indoor temperature and little direct sunlight – so I couldn’t identify any obvious external factors.

I would be interested in some insights: What could be the possible causes of these yellow stains on Kallax shelves made of wood-based material? Could they result from a chemical reaction within the material, moisture, light exposure, or something else? Are there any specific cleaning methods or precautions I should take to prevent further development of these stains?

Thank you in advance!

The yellow stains on your Kallax shelf are often caused by oxidation or a reaction of the resin-coated surface with UV light, even if direct sunlight exposure is minimal. IKEA uses melamine resin-coated particleboard, which can discolor over time, especially when moisture and temperature fluctuations are present.

In addition to UV exposure, contact with certain solvents or cleaning agents can roughen the surface and further worsen the yellowing. Gentle cleaning with a mild detergent without harsh chemicals helps prevent this. Moisture should be consistently kept low, as water can damage the particleboard beneath the surface laminate and promote yellowing.

The yellow stains on Kallax units are often caused by exposure to heat or grease marks. Check if you have placed the shelf near radiators or used it with warm objects. The best way to clean it is with a microfiber cloth and a little dish soap.

gauvin37 schrieb:
Often, the yellow stains on Kallax shelves are caused by heat exposure or grease marks.

Thank you, that’s a helpful suggestion. The shelf is actually located a few meters (several feet) away from a small portable heater, which is used quite frequently in winter. Do you think the yellow stains could really have been caused by that?

Siflo schrieb:
Melamine resin-coated particle boards can discolor due to UV exposure or moisture.

That makes moisture and cleaning agents relevant factors as well. In daily use, I only clean with a damp cloth and a mild all-purpose cleaner—no abrasive cloths or harsh chemicals.

Can anyone share more about the possible effects of heat sources on Kallax shelves? Or does anyone have experience with whether these stains eventually fade or if they are permanent?

The yellow stains you describe are most likely thermal discoloration, meaning a type of discoloration of the plastic coating caused by heat. The melamine resin surface of Kallax is sensitive to heat, and prolonged exposure can cause permanent color changes.

One way to prevent this problem in the future is to avoid placing direct heat sources near the shelf, such as space heaters or hot coffee cups directly on the surface. The stains usually do not fade on their own, as this is an irreversible change in the finish.

If you want to try to conceal the stains, very gentle sanding methods may be suitable, but use caution because sanding can damage the material. Applying a new surface seal or covering with adhesive film are other possible solutions.