Possible Clues:

• Shreds like cheese
• Rasps against, food or nerves
• The bits of rag set up where there's firing
• That's where they get fired - and one gets little thanks for being in there
• The firing there irritates one
• Rubs harshly against, perhaps on nerves
• It causes friction to have them in here
• Where there's firing things do not go smoothly
• No thanks getting in them where there's firing
• It gets a bit rough if one fires what's there