Answer: scum

AnswerCrossword Clue
SCUMGooey surface
SCUMNot a nice film
SCUMGrowth on some ponds
SCUMIcky pond surface
SCUMIcky residue
SCUMLowest of the low
SCUMSurface muck
SCUMGrimy coating
SCUMUgly pond film
SCUMPond skimmer's target
SCUMUndesirable sorts
SCUMRiffraff
SCUMPond floater
SCUMBathtub woe
SCUMGrimy residue
SCUMBathtub buildup
SCUMAquarium growth
SCUMScrubbing Bubbles target
SCUMPond build-up
SCUMBathtub residue
scumto remove waste from
SCUMSoap residue
SCUMPond gunk
SCUMPond surface
SCUMFoul film
SCUMDross
SCUMLowlife
SCUMBath tile residue
SCUMLowlifes
SCUMSoap film
SCUMDirty film
SCUMTilex target
SCUMPond film
SCUMPond problem
SCUMFountain build-up
SCUMFilm on water
SCUMMr. Clean target
SCUMPond surface, perhaps
SCUMThe head on beer, essentially
SCUMPond covering