I remember every Erev Tisha B'Av looking for something to burn to create ashes. A napkin starts floating around the room and might burn something, etc.
Then I was at a Chasunah and I saw Rav Berkovits strike the match, let it burn down almost to his fingers, then break off the top with the sulfur and crush the rest, creating ash for the chosson.
Maybe this is obvious but it never occurred to me...