Firefighters found this onion bomb hidden in bushes in Salford near where the boys were injured.
They've confiscated it and are warning of the dangers of fireworks.
Onion bombs aren't meant to be available to the public.
More top news
Frost and fog overnight into Monday. Turning milder this week
Cold start but turning milder this week.
Churches in parts of Manchester are urging people to bin their blades in the run up to Christmas.