Oops.. you slipped a post in there on me. your talking about the stem I take it. mold is something you'll want to watch out for. to create it you will need a humid and warm stagnant environment. that looks to be discoloration. mold will have fuzz in most cases.

Skip the rolling pin. get a spark plug socket. its less unruly and if you end up needing it, its much easier.

Congratulations! you've done it and, a shaggy foot pyramid for you first stick at that. nice! Leaf count can get tricky given they very in size. Weight is the best measure.