Bang it lightly with your fist until it clicks. Enjoy fresh ground pepper.
I've developed a taste for fresh ground pepper, but as someone on a low salary I don't want to buy an expensive pepper mill. Some spice companies sell peppercorns, sea salt grains, and dried spices etc. in neat little grinders, but you're not supposed to be able to refill them, which is a bit silly since you can buy bulk spices much cheaper from most supermarkets.
Step 1: Oops
My first attempt at getting the plastic grinder top off the glass container went badly. I tried to use a spoon to pry it off, wedging the end of the spoon into the lid and banging it on the table. It made some cracking noises, which I thought was glue. It turned out that I'd broken the rim of the glass bottle off.