(n.) A substance which removes color, or bleaches.

achromatization achromatize besnow blanch blanching bleach out bleacher bleaching bleaching agent bleaching powder blench bowdlerize chalk change color chlorine clean clean out clean up cleanse clear out decolor decolorant decoloration decolorization decolorize decolorizer decolorizing delouse depurate deterge dim discolor discoloration drain drain of color dry-clean dull dust dust off etiolate etiolation expurgate fade fade out fading freshen frost fume grizzle grow pale hydrochloric acid hydrogen peroxide lighten lightening lime lose color lustrate madder bleach market bleach nitrogen tetroxide oxalic acid pale paling peroxide purge purify reform scavenge silver sodium hypochlorite sour spruce steam-clean sulfur dioxide sulfuric acid sweep out sweeten tarnish tidy tone down turn pale turn white wan wash out white white sour whiten whitening wipe wipe off wipe out wipe up