"Dust a sound boy" (or dust a soundbwoy) is Jamaican sound clash slang that means to defeat, destroy, or completely outplay a rival DJ/sound system crew in a music competition.
Dust: To leave an opponent in the dust; to defeat them so thoroughly they are "turned to dust" or eliminated from the competition.
Sound Boy (Soundbwoy): A member, selector (DJ), or operator of a rival sound system. In sound system culture, calling an opponent a "sound boy" is slightly diminutive—it frames them as an amateur, an inexperienced youth, or someone lacking skills.
The phrase was famously popularized by Super Beagle in his 1991 reggae/dancehall hit "Dust A Sound Boy" (produced by Winston Riley on the iconic Stalag 17 riddim).
The vocal intro and lyrics from this track have been sampled extensively across hip-hop, jungle, and dubstep, most notably in Kanye West’s 2012 hit "Mercy" (which samples Fuzzy Jones' intro from the track).