They might be glowing

EMBERS

Think of what remains after a fire has mostly burned out, often still holding a faint, warm light.

"Embers" fits because they’re the small, glowing pieces left after a fire burns down. The clue plays on the idea of something literally glowing—embers do exactly that, giving off a warm, faint light. It’s a straightforward definition without hidden wordplay, just a vivid way to describe what embers look like when they’re still hot.