Acrylic mahjong tiles are durable, but a few habits will keep the engraving crisp and the surface from clouding over years of play.
Everyday cleaning
Wipe tiles with a soft, slightly damp microfiber cloth after game nights, especially if snacks and drinks were involved at the table. Avoid soaking tiles or running them under water — moisture can seep into the engraved numerals and dull the color fill over time.
What to avoid
Skip harsh solvents, bleach, and abrasive sponges. These can strip the paint fill from engraved tiles and leave micro-scratches that dull the surface finish. A mild soap diluted in water, applied with a soft cloth, is enough for most spills.
Storage
Store tiles in their case or a padded bag rather than loose in a drawer. Direct sunlight over long periods can fade colored tile backs, so keep the case somewhere shaded. Racks should be stored flat to avoid warping the pusher mechanism.
Between games
A quick wipe-down before tiles go back in the case takes under a minute and is the single biggest thing you can do to keep a set looking new for years of regular play.