Always put your trading cards in poly sleeves before putting them in cardboard storage boxes. Most cardboard boxes are not acid-free and the acid in them and in the environment can easily be shared with your cards – contributing to the premature aging of your cards. We do stock an acid-free storage box for trading cards and recommend it for your more valuable cards.
https://www.bagsunlimited.com/product/5902/trading-card-boxes
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