convert (metallic mercury) into a grey powder consisting of minute globules, as by shaking with chalk or fatty oil(verb.change)
source: wordnet30
To make as dead; to impair in vigor, force, activity, or sensation; to lessen the force or acuteness of; to blunt; as, to deaden the natural powers or feelings; to deaden a sound.(verb)
source: webster1913
To render impervious to sound, as a wall or floor; to deafen.(verb)