Powders in jars (6)
I believe the answer is:
grates
But I can't explain it at all! Could you help me understand?
(Other definitions for grates that I've seen before include "Makes rasping sound, hard on ear" , "Rubs harshly against, perhaps on nerves" , "Makes harsh noise by rubbing - on nerves?" , "Rasps against, food or nerves" , "Makes harsh sound by rubbing" .)