Build a UV-light box to restore discolored Lego

Apart from being dirty and sometimes warped, old bricks come with another handicap: they yellow over time. This is especially the case with white bricks and less so for grey and blue. It turns out this yellowing can be undone using hydro-peroxide and UV light. There are many video’s on YouTube showing how this can be done using sunlight. However, since The Netherlands is not the sunniest of places and since I did not want to be dependent on the availability of sunlight, I decided to build a UV light box to restore the color of my yellowed bricks. It uses 4 UV fluorescent tubes, 2 above and 2 below, and two Ikea transparent boxes to hold each 5 liters of 3% hydro-peroxide and the Lego bricks. Initially soaking for 3 hours with 30 minute stirs and after many batches up to 6 hours, with 1 hour stirring – the peroxide is re-used but concentration reduces over time – will do the trick.


    1. Hi! Thanks for your interest. Unfortunately I have no plans. Building one to sell would not be economical. The way I approached this was by starting out with buying two transparent boxes from IKEA and then design the box around it to match. It’s made from 9 mm birch plywood cut to size with a Makita track saw and guide rail (precise working required!) and then glue everything together. A table saw would be easier but at the time I did not have one. 4 UV florescent light tubes are fitted powered from one electronic device that is capable of feeding 4 tubes. I used two multi-core cables to power the tubes in the lid. I’ve the option of inserting the 2 bottom tubes in the lid also allowing the cabinet to be used for printed circuit board (PCB) fabrication. Haven’t used that option yet.



  1. Hello, what wavelength are the bulbs you are using? I have a similar setup, but think my wavelength must be off. Thanks!



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