SLAG

Stony waste matter (in a heap?) (4)

Solution has appeared in 2 crosswords (2 across and 0 down):

• Quick crossword No 15,990 — 2021-08-05 23:00:07
  20A: Solid scum on molten metal (4)
• Quick crossword No 15,792 — 2020-12-17 00:00:23
  20A: Stony waste matter (in a heap?) (4)