Gunk

google

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1930s (originally US): the proprietary name of a detergent.

wiktionary

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Apparently from Gunk, trademark name for a liquid soap; perhaps taken as a blend of grime +‎ funk.

etymonline

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gunk (n.)

"viscous substance," 1949, American English, apparently from Gunk, trademark for a thick liquid soap patented 1932 by A.F. Curran Co. of Malden, Mass.