SINCE 1828

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acid-free

adjective

Definition of acid-free

:not containing acid :having a neutral or alkaline pH

acid-free paper

Every evening, trained volunteers will place any personal items or memorabilia left at the replica wall in archival folders or acid-free boxes.
—Brian Burnes, Kansas City Star, 22 Sept. 2010

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First Known Use of acid-free

1885

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