Found millions on the patio when lighting BBQ last Saturday.
Found a crack in the concrete where there were coming from.
Found I had some 2 stroke mix handy as had been cutting grass all afternoon.
(think I know where this is going)
2 stroke mix found its way into crack in concrete.
2 stroke mix ignited with a lighter I found in my pocket.
2 stroke mix did the job.
Woosh.