Related Clues:

• Volcano flower
• A grate build-up
• Close-grained wood
• It's a grate thing
• Waste at a foundry
• Soft rock?
• Blast furnace byproduct
• Remains in the tray
• Volcanic outflow
• Hand soap brand
• Burnt residue
• Mantle piece?
• Leaving after the barbecue
• Wednesday smudge
• Volcano outflow