An Etymological Dictionary of the German Language/Annotated/spülen
spülen, verb, ‘to rinse, wash,’ from the equivalent Middle High German spüelen, Old High German spuolen, weak verb; corresponding to the equivalent Dutch spoelen, Anglo-Saxon spêlan. Its connection with the preceding word is not clear. — The corresponding collective Spülicht, neuter, ‘dish-wash, swill,’ is based on Middle High German spüelach (Old High German *spuolahi).